Immunoconjugates

ABSTRACT

The present invention generally relates to antigen-specific immunoconjugates for selectively delivering effector moieties that influence cellular activity. More specifically, the invention provides novel immunoconjugates comprising a first antigen binding moiety, an Fc domain and a single effector moiety. In addition, the present invention relates to polynucleotides encoding such immunoconjugates, and vectors and host cells comprising such polynucleotides. The invention further relates to methods for producing the immunoconjugates of the invention, and to methods of using these immunoconjugates in the treatment of disease.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 13/457,039, filed Apr. 26, 2012, now U.S. Pat. No. 9,447,159, issued Sep. 20, 2016, which claims benefit under 35 U.S.C. § 119 to European Patent Application No. 11164237.7, filed Apr. 29, 2011, the contents of which are hereby incorporated by reference.

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created Mar. 9, 2018, is named P27307_US_3_SeqListing.txt and is 494,061 bytes in size.

FIELD OF THE INVENTION

The present invention generally relates to antigen-specific immunoconjugates for selectively delivering effector moieties that influence cellular activity. In addition, the present invention relates to polynucleotides encoding such immunoconjugates, and vectors and host cells comprising such polynucleotides. The invention further relates to methods for producing the immunoconjugates of the invention, and to methods of using these immunoconjugates in the treatment of disease.

BACKGROUND

The selective destruction of an individual cell or a specific cell type is often desirable in a variety of clinical settings. For example, it is a primary goal of cancer therapy to specifically destroy tumor cells, while leaving healthy cells and tissues intact and undamaged. A multitude of signal transduction pathways in the cell are linked to the cell's survival and/or death. Accordingly, the direct delivery of a pathway factor involved in cell survival or death can be used to contribute to the cell's maintenance or destruction. Similarly, specific factors may be delivered that stimulate immune effector cells in a tumor microenvironment, such as natural killer (NK) cells or cytotoxic T lymphocytes (CTLs), to attack and destroy tumor cells.

Cytokines are cell signaling molecules that participate in regulation of the immune system. When used in cancer therapy, cytokines can act as immunomodulatory agents that have anti-tumor effects and which can increase the immunogenicity of some types of tumors. However, rapid blood clearance and lack of tumor specificity require systemic administration of high doses of the cytokine in order to achieve a concentration of the cytokine at the tumor site sufficient to activate an immune response or have an anti-tumor effect. These high levels of systemic cytokine can lead to severe toxicity and adverse reactions.

For use in therapy, it is therefore desirable to specifically deliver a signal transduction pathway factor, such as a cytokine, to a specific site in vivo (e.g. a tumor or tumor microenvironment in the case of cancer therapy). This can be achieved by conjugating the factor to a targeting moiety, e.g. an antibody or an antibody fragment, specific for the site. Early strategies aimed at delivering signal transduction pathway factors, such as cytokines, to a specific site in vivo included immunoglobulin heavy chains conjugated to various cytokines, including lymphotoxin, tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), and granulocyte macrophage-colony stimulating factor (GM-CSF) (reviewed e.g. in Lode et al., Pharmacol Ther 80, 277-292 (1998)).

Researchers observed that, not only were they able to target cytokines to specific sites in vivo, they were also able to take advantage of the fact that monoclonal antibodies have longer serum half-lives than most other proteins. Given the systemic toxicity associated with high doses of certain unconjugated cytokines, e.g. IL-2, the ability of an immunoglobulin-cytokine fusion protein to maximize therapeutically beneficial biological activities at a desired site, e.g. in a tumor, whilst keeping systemic side effects to a minimum at a lower dose led researchers to believe that immunoglobulin-cytokine immunoconjugates were optimal therapeutic agents.

Nevertheless, there are certain disadvantages associated with the immunoglobulin-cytokine immunoconjugtates known in the art. For example, these immunoconjugates have at least one cytokine coupled to each of the two immunoglobulin heavy chains, resulting in an immunoconjugate with bivalent target binding and two or more cytokine moieties (reviewed e.g. in Chang et al., Expert Opin Drug Discovery 4, 181-194 (2009), or Ortiz-Sanchez et al., Expert Opin Biol Ther 8, 609-632 (2008)). FIG. 1 depicts a conventional immunoglobulin-cytokine immunoconjugate as it is known in the art, where a cytokine is fused to the C-terminus of each of the two antibody heavy chains. Due to the presence of two or more cytokine moieties, such an immunoconjugate has a high avidity to the respective cytokine receptor (for example, picomolar affinity in the case of IL-2), and thus is targeted rather to the immune effector cells expressing the cytokine receptor than to the target antigen of the immunoglobulin (nM affinity) to which the cytokine is linked. Moreover, conventional immunoconjugates are known to be associated with infusion reactions (see e.g. King et al., J Clin Oncol 22, 4463-4473 (2004)), resulting at least partially from activation of cytokine receptors on immune effector cells in peripheral blood by the immunoconjugate's cytokine moieties.

Additionally, via their Fc domain, immunoglobulin-cytokine immunoconjugates can activate complement and interact with Fc receptors. This inherent immunoglobulin feature has been viewed unfavorably because therapeutic immunoconjugates may be targeted to cells expressing Fc receptors rather than the preferred antigen-bearing cells. Moreover, the simultaneous activation of cytokine receptors and Fc receptor signaling pathways leading to cytokine release, especially in combination with the long half-life of immunoglobulin fusion proteins, make their application in a therapeutic setting difficult due to systemic toxicity.

One approach to overcoming this problem is the use of immunoglobulin fragments devoid of an Fc domain, such as scFv or Fab fragments, in immunoconjugates. Examples of immunoglobulin fragment-cytokine immunoconjugates include the scFv-IL-2 immunoconjugate as set forth in PCT publication WO 2001/062298, the scFv-IL-12-scFv immunoconjugate as set forth in PCT publication WO 2006/119897 (wherein each of the two scFv fragments is connected to a subunit of the IL-12 heterodimer that is held together by disulfide bond(s)) or the Fab-IL-2-Fab immunoconjugates as set forth in PCT publication WO 2011/020783. Both the tumor-binding reactivity of the immunoglobulin parent molecule and the functional activity of the cytokine are maintained in most of these types of immunoconjugates, however the half-life of such constructs is considerably shorter than of immunoglobulin fusion proteins.

Therefore there remains a need for immunoconjugates with improved properties, for greater therapeutic effectiveness and a reduction in the number and severity of the side effects of these products (e.g., toxicity, destruction of non-tumor cells, etc.).

The present invention provides immunoglobulin-like immunoconjugates that exhibit improved efficacy, high specificity of action, reduced toxicity, and improved half-life and stability in blood relative to known immunoconjugates.

SUMMARY OF THE INVENTION

The present invention is based, in part, on the inventors' recognition that immunoconjugates comprising more than one effector moiety, such as e.g. a cytokine, may be targeted to the respective effector moiety receptor rather than the target antigen of the antigen binding moiety of the immunoconjugate. Therefore, in one aspect the invention provides an immunoconjugate comprising a first antigen binding moiety, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. In one embodiment the effector moiety is fused to the amino- or carboxy-terminal amino acid of one of the two subunits of the Fc domain, optionally through a linker peptide. In one embodiment the first antigen binding moiety is fused to the amino-terminal amino acid of one of the two subunits of the Fc domain, optionally through a linker peptide or an immunoglobulin hinge region.

In one embodiment the first antigen binding moiety comprises an antigen binding domain of an antibody. In a particular embodiment the first antigen binding moiety is a Fab molecule. In certain embodiments the Fc domain comprises a modification promoting heterodimerization of two non-identical polypeptide chains. In a specific embodiment said modification is a knob-into-hole modification, comprising a knob modification in one of the subunits of the Fc domain and a hole modification in the other one of the two subunits of the Fc domain. In a particular embodiment the effector moiety is fused to the amino- or carboxy-terminal amino acid of the subunit of the Fc domain comprising the knob modification.

In one embodiment the Fc domain is an IgG Fc domain, particularly an IgG₁ Fc domain. In a particular embodiment the Fc domain is human.

In certain embodiments of the invention the Fc domain is engineered to have altered binding to an Fc receptor, specifically altered binding to an Fcγ receptor, and/or altered effector function, specifically altered antibody-dependent cell-mediated cytotoxicity (ADCC).

Although the presence of an Fc domain is essential for prolonging the half-life of the immunoconjugate, the inventors realize that in some situations it will be beneficial to eliminate effector functions associated with engagement of Fc receptors by the Fc domain. Hence, in particular embodiments the altered binding to an Fc receptor and/or effector function is reduced binding and/or effector function. In a specific such embodiment the Fc domain comprises one or more amino acid mutation that reduces the binding of the Fc domain to an Fc receptor, particularly an Fcγ receptor. Preferably, such an amino acid mutation does not reduce binding to FcRn receptors. In one embodiment the Fc domain comprises an amino acid substitution at position P329. In a particular embodiment the Fc domain comprises the amino acid substitutions L234A, L235A and P329G in each of its subunits.

On the other hand, there may be situations where it is desirable to enhance the effector functions of immunoconjugates. Hence, in certain embodiments the Fc domain of the immunoconjugate of the invention is engineered to have altered binding to an Fc receptor, specifically an Fcγ receptor, more specifically an FcγIIIa receptor, and/or altered effector function, wherein the altered binding and/or effector function is increased binding and/or effector function. In one such embodiment the Fc domain is engineered to have an altered oligosaccharide structure, as compared to a non-engineered Fc domain. In a particular such embodiment the Fc domain comprises an increased proportion of non-fucosylated oligosaccharides, as compared to a non-engineered Fc domain. In a more specific embodiment the Fc domain comprises at least 20%, particularly at least 50%, more particularly at least 70% non-fucosylated oligosaccharides. In another specific embodiment the Fc domain comprises an increased proportion of bisected oligosaccharides, as compared to a non-engineered Fc domain. In yet another specific embodiment the Fc domain comprises an increased proportion of bisected, non-fucosylated oligosaccharides, compared to a non-engineered Fc domain. In some embodiments said altered oligosaccharide structure results from increased β(1,4)-N-acetylglucosaminyltransferase III (GnTIII) activity in a host cell used for expression of the immunoconjugate.

In a particular aspect, the invention provides immunoconjugates that comprise a first and a second antigen binding moiety, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. In one embodiment the first and the second antigen binding moiety and the Fc domain are part of an immunoglobulin molecule. In certain embodiments the immunoconjugate essentially consists of an immunoglobulin molecule and an effector moiety and optionally one or more linker sequences. In a particular embodiment the immunoglobulin molecule is an IgG class immunoglobulin. In an even more particular embodiment the immunoglobulin is an IgG₁ subclass immunoglobulin. In one embodiment the effector moiety is fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, optionally through a linker peptide.

In a particular embodiment the immunconjugate of the invention comprises an immunoglobulin molecule comprising two antigen binding moieties and an Fc domain, and an effector moiety fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, wherein not more than one effector moiety is present and wherein the Fc domain is engineered to have reduced binding to an Fc receptor, specifically altered binding to an Fcγ receptor, and/or reduced effector function.

In certain embodiments said first antigen binding moiety, or said first and said second antigen binding moiety, is directed to an antigen associated with a pathological condition, such as an antigen presented on a tumor cell or in a tumor cell environment, at a site of inflammation, or on a virus-infected cell. In a more specific embodiment said antigen is selected from the group of Fibroblast Activation Protein (FAP), the A1 domain of Tenascin-C (TNC A1), the A2 domain of Tenascin-C (TNC A2), the Extra Domain B of Fibronectin (EDB), Carcinoembryonic Antigen (CEA), and Melanoma-associated Chondroitin Sulfate Proteoglycan (MCSP).

In certain embodiments the effector moiety is a single chain effector moiety. In a particular embodiment the effector moiety is a cytokine. In one embodiment said cytokine is selected from the group of IL-2, IL-7, IL-10, IL-12, IL-15, IFN-α and IFN-γ. In a particular embodiment said cytokine is IL-2. In an even more particular embodiment said cytokine is a mutant IL-2 polypeptide having reduced binding affinity to the α-subunit of the IL-2 receptor. In a specific embodiment said mutant IL-2 polypeptide comprises an amino acid substitution at one or more positions selected from the positions corresponding to residues 42, 45 and 72 of human IL-2. In another particular embodiment the cytokine is IL-10. In yet another embodiment, the cytokine is IL-15, particularly a mutant IL-15 polypeptide having reduced binding affinity to the α-subunit of the IL-15 receptor. In another embodiment, the cytokine is IFN-α.

According to another aspect of the invention there is provided an isolated polynucleotide encoding an immunoconjugate of the invention or a fragment thereof. The invention further provides an expression vector comprising the isolated polynucleotide of the invention, and a host cell comprising the isolated polynucleotide or the expression vector of the invention. In some embodiments the host cell is a eukaryotic cell, particularly a mammalian cell. In some embodiments, the host cell has been manipulated to express increased levels of one or more polypeptides having β(1,4)-N-acetylglucosaminyltransferase III (GnTIII) activity. In one such embodiment the host cell has been further manipulated to express increased levels of one or more polypeptides having α-mannosidase II (ManII) activity.

In another aspect is provided a method of producing the immunoconjugates of the invention, comprising the steps of a) culturing the host cell of the invention under conditions suitable for the expression of the immunoconjugate and b) recovering the immunoconjugate. The invention also encompasses an immunoconjugate produced by the method of the invention.

The invention further provides a pharmaceutical composition comprising an immunoconjugate of the invention and a pharmaceutically acceptable carrier.

Also encompassed by the invention are methods of using the immunoconjugates and pharmaceutical compositions of the invention. In one aspect the invention provides an immunoconjugate or a pharmaceutical composition of the invention for use as a medicament. In one aspect is provided an immunoconjugate or a pharmaceutical composition according to the invention for use in the treatment of a disease in an individual in need thereof. In a specific embodiment the disease is cancer. In other embodiments the disease is an inflammatory disorder. In a particular such embodiment the immunoconjugate comprises an IL-10 effector moiety.

Also provided is the use of an immunoconjugate of the invention for the manufacture of a medicament for the treatment of a disease in an individual in need thereof as well as a method of treating a disease in an individual, comprising administering to said individual a therapeutically effective amount of a composition comprising the immunoconjugate according to the invention in a pharmaceutically acceptable form. In a specific embodiment the disease is cancer. In other embodiments the disease is an inflammatory disorder. In a particular such embodiment the immunoconjugate comprises an IL-10 effector moiety.

In any of the above embodiments the individual preferably is a mammal, particularly a human.

In a further aspect, the invention provides a conjugate comprising a first Fab molecule which does not specifically bind any antigen, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. In a particular embodiment the first Fab molecule comprises the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297. In one embodiment, the effector moiety is fused to the amino- or carboxy-terminal amino acid of one of the two subunits of the Fc domain, optionally through a linker peptide. In another embodiment, the first Fab molecule is fused to the amino-terminal amino acid of one of said two subunits of the Fc domain, optionally through a linker peptide or an immunoglobulin hinge region. In one embodiment, the conjugate comprises (i) an immunoglobulin molecule, comprising a first and a second Fab molecule which do not specifically bind any antigen and an Fc domain, and (ii) an effector moiety, wherein not more than one effector moiety is present. In one embodiment the immunoglobulin molecule is an IgG class immunoglobulin, particularly an IgG1 subclass immunoglobulin. In a particular embodiment the immunoglobulin molecule comprises the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297.

Specifically, the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297 are comprised in the first and the second Fab molecule of the immunoglobulin molecule. In one embodiment, the effector moiety is fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, optionally through a linker peptide.

In certain embodiments the Fc domain of the conjugate comprises a modification promoting heterodimerization of the non-identical polypeptide chains. In a specific embodiment, said modification is a knob-into-hole modification, comprising a knob modification in one of the subunits of the Fc domain and a hole modification in the other one of the two subunits of the Fc domain. In a particular embodiment, the effector moiety is fused to the amino- or carboxy-terminal amino acid of the subunit of the Fc domain comprising the knob modification. In one embodiment, the Fc domain is an IgG Fc domain, particularly an IgG₁ Fc domain. In a particular embodiment, the Fc domain is human. In some embodiments, the Fc domain is engineered to have altered binding to an Fc receptor, specifically altered binding to an Fcγ receptor, and/or altered effector function, specifically altered ADCC. In some embodiments the Fc domain of the conjugate is engineered to have reduced binding to an Fc receptor, specifically reduced binding to an Fcγ receptor, and/or reduced effector function, specifically reduced ADCC. In one embodiment, the Fc domain comprises one or more amino acid mutation that reduces the binding of the Fc domain to an Fc receptor, particularly an Fcγ receptor. In a specific embodiment the amino acid mutation is an amino acid substitution at position P329. In a particular embodiment, the Fc domain of the conjugate comprises the amino acid substitutions L234A, L235A and P329G in each of its subunits. In another embodiment of the conjugate of the invention, the Fc domain is engineered to have altered binding to an Fc receptor and/or altered effector function, wherein said altered binding and/or effector function is increased binding and/or effector function. In one embodiment of the conjugate of the invention, the Fc domain is engineered to have an altered oligosaccharide structure, as compared to a non-engineered Fc domain. In a specific embodiment, the Fc domain described above comprises an increased proportion of non-fucosylated oligosaccharides, as compared to a non-engineered Fc domain.

In a further embodiment of the conjugate of the invention, the conjugate comprises a first and a second Fab molecule. In one embodiment, the first and the second Fab molecule each comprises the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297. In one embodiment, the first and said second Fab molecule and said Fc domain are part of an immunoglobulin molecule. In a particular embodiment, the immunoglobulin molecule is an IgG class immunoglobulin. In an even more particular embodiment, the immunoglobulin molecule is an IgG₁ subclass immunoglobulin. In one embodiment, the effector moiety is fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, optionally through a linker peptide.

In some embodiments of the conjugate of the invention, said effector moiety is a single chain effector moiety. In one embodiment the effector moiety is a cytokine, particularly IL-2. In another embodiment, said cytokine is a mutant IL-2 polypeptide having reduced binding affinity to the α-subunit of the IL-2 receptor. In a specific embodiment, said mutant IL-2 polypeptide comprises an amino acid substitution at one or more positions selected from the positions corresponding to residues 42, 45 and 72 of human IL-2.

Additionally, the conjugate can incorporate, alone or in combination, any of the features described herein in relation to the formats, the Fc domain or the effector moiety of the immunoconjugates of the invention.

The invention also provides an isolated polynucleotide encoding the conjugate of the invention of a fragment thereof, as described above. In a specific embodiment, the isolated polynucleotide comprises a sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 298 or SEQ ID NO: 300. The invention further provides an expression vector comprising the isolated polynucleotide, and a host cell comprising the isolated polynucleotide or the expression vector of the invention. In another aspect is provided a method of producing the conjugate of the invention described above, comprising the steps of a) culturing the host cell of the invention under conditions suitable for the expression of the conjugate and b) recovering the conjugate. The invention also encompasses a conjugate, described above, produced by the method of the invention, comprising the steps of a) culturing the host cell of the invention under conditions suitable for the expression of the conjugate and b) recovering the conjugate.

The invention further provides a pharmaceutical composition comprising the conjugate of the invention described above and a pharmaceutically acceptable carrier. Furthermore, the conjugate can be employed in the methods of use described herein for the immunoconjugates of the invention. In one embodiment, the conjugate as described above, or the pharmaceutical composition described above, is for use in the treatment of a disease in an individual in need thereof or for the manufacture of a medicament for the treatment of a disease in an individual in need thereof.

In a further aspect of the invention, a method of treating a disease in an individual is provided, comprising administering to said individual a therapeutically effective amount of a composition comprising the conjugate of the invention as described above, in a pharmaceutically acceptable form.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Schematic representation of typical immunoglobulin-cytokine immunoconjugate as known in the art, with a cytokine (dotted) fused to the C-terminus of each of the two immunoglobulin heavy chains.

FIGS. 2A-C. Schematic representation of novel immunoconjugates according to the invention, comprising not more than one effector moiety (dotted). The effector moiety is fused, optionally via a linker peptide (grey boxes) to the carboxy-terminal (FIGURES A and B) or the amino-terminal amino acid (FIGURE C) of the Fc domain. The immunoconjugate comprises one (FIGURES B and C) or more (typically two, FIGURE A) antigen binding moieties, which may be Fab fragments comprising antibody heavy and light chain variable domains (hatched). The Fc domain may comprise a modification promoting heterodimerization of two non-identical polypeptide chains (black dot) and/or a modification altering Fc receptor binding and/or effector function (black star).

FIGS. 3A-D. Purification of FAP-targeted 4G8-based IgG-IL-2 quadruple mutant (qm) immunoconjugate. FIG. 3A) Elution profile of the Protein A affinity chromatography step. FIG. 3B) Elution profile of the size exclusion chromatography step. FIG. 3C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 3D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (97% monomer content).

FIGS. 4A-D. Purification of FAP-targeted 28H1-based IgG-IL-2 qm immunoconjugate. FIG. 4A) Elution profile of the Protein A affinity chromatography step. FIG. 4B) Elution profile of the size exclusion chromatography step. FIG. 4C) Analytical SDS-PAGE (reduced: NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer; non-reduced: NuPAGE Tris-Acetate, Invitrogen, Tris-Acetate running buffer) of the final product. FIG. 4D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (100% monomer content).

FIGS. 5A-D. Purification of FAP-targeted 28H1-based IgG-IL-2 qm immunoconjugate from CHO cells. FIG. 5A) Elution profile of the Protein A affinity chromatography step. FIG. 5B) Elution profile of the size exclusion chromatography step. FIG. 5C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 5D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (100% monomer content).

FIGS. 6A-D. Purification of FAP-targeted 4B9-based IgG-IL-2 qm immunoconjugate. FIG. 6A) Elution profile of the Protein A affinity chromatography step. FIG. 6B) Elution profile of the size exclusion chromatography step. FIG. 6C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 6D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (100% monomer content).

FIGS. 7A-D. Purification of CEA-targeted CH1A1A 98/99 2F1-based IgG-IL-2 qm immunoconjugate. FIG. 7A) Elution profile of the Protein A affinity chromatography step. FIG. 7B) Elution profile of the size exclusion chromatography step. FIG. 7C) Analytical capillary electrophoresis SDS (Caliper) of the final product. FIG. 7D) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (98.8% monomer content).

FIGS. 8A-D. Purification of TNC A2-targeted 2B10-based IgG-IL-2 qm immunoconjugate. FIG. 8A) Elution profile of the Protein A affinity chromatography step. FIG. 8B) Elution profile of the size exclusion chromatography step. FIG. 8C) Analytical capillary electrophoresis SDS (Caliper) of the final product. FIG. 8D) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (100% monomer content).

FIGS. 9A-D. Purification of untargeted DP47GS-based IgG-IL-2 qm immunoconjugate. FIG. 9A) Elution profile of the Protein A affinity chromatography step. FIG. 9B) Elution profile of the size exclusion chromatography step. FIG. 9C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 9D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (100% monomer content).

FIG. 10. Binding of FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate to human FAP expressed on stably transfected HEK 293 cells as measured by FACS, compared to the corresponding Fab-IL-2 qm-Fab construct.

FIG. 11. Interferon (IFN)-γ release on NK92 cells induced by FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate in solution, compared to the 28H1-based Fab-IL-2 qm-Fab construct.

FIGS. 12A-D. Detection of phosphorylated STAT5 by FACS in different cell types after stimulation for 20 min with FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate in solution, compared to the 28H1-based Fab-IL-2-Fab and Fab-IL-2 qm-Fab constructs as well as Proleukin. FIG. 12A) NK cells (CD3⁻CD56⁺); FIG. 12B) CD8⁺ T cells (CD3⁺CD8⁺); FIG. 12C) CD4⁺ T cells (CD3⁺CD4⁺CD25⁻CD127⁺); FIG. 12D) regulatory T cells (CD4⁺CD25⁺FOXP3⁺).

FIG. 13. Binding of TNC A2-targeted 2B10 IgG-IL-2 qm and corresponding unconjugated IgG to TNC A2-expressing U87MG cells, as measured by FACS.

FIG. 14. Induction of NK92 cell proliferation by TNC A2-targeted 2B10 IgG-IL-2 qm, CEA-targeted CH1A1A 98/99 2F1 IgG-IL-2 qm and CH1A1A 98/99 2F1 IgG-IL-2 wt immunoconjugates.

FIG. 15. Induction of NK92 cell proliferation by FAP-targeted 4B9 IgG-IL-2 qm and 4B9 IgG-IL-2 wt immunoconjugates.

FIG. 16. Killing (as measured by LDH release) of CEA-overexpressing A549 tumor cells by PBMCs through ADCC mediated by glycoengineered (ge) and wildtype (wt) CH1A1A IgG-IL-2 qm immunoconjugates, compared to unconjugated glycoengineered CH1A1A IgG.

FIGS. 17A-D. Purification of untargeted DP47GS IgG-IL-2 wt immunoconjugate. FIG. 17A) Elution profile of the Protein A affinity chromatography step. FIG. 17B) Elution profile of the size exclusion chromatography step. FIG. 17C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 17D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (99.6% monomer content).

FIGS. 18A-D. Purification of 28H1-based FAP-targeted 28H1 IgG-IL-2 wt immunoconjugate. FIG. 18A) Elution profile of the Protein A affinity chromatography step. FIG. 18B) Elution profile of the size exclusion chromatography step. FIG. 18C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 18D) Analytical size exclusion chromatography of the final product on a Superdex 200 column (99.6% monomer content).

FIGS. 19A-D. Purification of CEA-targeted CH1A1A 98/99 2F1-based IgG-IL-2 wt immunoconjugate. FIG. 19A) Elution profile of the Protein A affinity chromatography step. FIG. 19B) Elution profile of the size exclusion chromatography step. FIG. 19C) Analytical capillary electrophoresis SDS (Caliper) of the final product. FIG. 19D) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (100% monomer content).

FIGS. 20A-D. Purification of FAP-targeted 4B9-based IgG-IL-2 wt immunoconjugate. FIG. 20A) Elution profile of the combined Protein A affinity and size exclusion chromatography. FIG. 20B) Zoom on the elution profile of the size exclusion chromatography step in A. FIG. 20C) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 20D) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (98.5% monomer content).

FIGS. 21A-C. FIG. 21A) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel (Invitrogen), NuPAGE LDS sample buffer (4×), heated for 10 min at 70° C., MOPS buffer, 160 V, 60 min, MW marker Mark 12, unstained standard (Invitrogen, M) of reduced (1) and non-reduced (2) 2B10 IgG-IL-10M1. FIG. 21B) SPR-based affinity determination (ProteOn XPR36) of 2B10 IgG-IL-10M1 to human TNC A2 fitted globally to a 1:1 interaction model. (chip: NLC; ligand: TNCA2 (250 RU); analyte: TNCA2 2B10 IgG-IL-10M1 164 kDa; concentration range analyte: 50, 10, 2, 0.4, 0.08, 0 nM; association time: 180 s; dissociation time: 600 s; flow rate: 50 μl/min; k_(on) 1.80×10⁶ l/Ms; k_(off): 9.35×10⁻⁵ l/s; K_(D): 52 pM). FIG. 21C) SPR-based affinity determination (ProteOn XPR36) of 2B10 IgG-IL-10M1 to human IL-10R1 fitted globally to a 1:1 interaction model (chip: NLC; ligand: IL-10R1 (1600RU); analyte: TNCA2 2B10 IgG-IL-10M1 164 kDa; concentration range analyte: 50, 10, 2, 0.4, 0.08, 0 nM; association time: 180 s; dissociation time: 600 s; flow rate: 50 μl/min; k_(on) 5.56×10⁵ l/Ms; k_(off): 2.89×10⁻⁴ l/s; K_(D): 520 pM).

FIGS. 22A-C. FIG. 22A) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel (Invitrogen), NuPAGE LDS sample buffer (4×), heated for 10 min at 70° C., MOPS buffer, 160 V, 60 min, MW marker Mark 12, unstained standard (Invitrogen, M) of reduced (1) and non-reduced (2) 4G8 IgG-IL-10M1. FIG. 22B) SPR-based affinity determination (ProteOn XPR36) of 4G8 IgG-IL-10M1 to human FAP fitted globally to a 1:1 interaction model (chip: GLM; ligand: huFAP (500RU); analyte: FAP 4G8 IgG-IL-10M1 164 kDa; concentration range analyte: 10, 2, 0.4, 0.08, 0 nM; association time: 180 s; dissociation time: 600 s; flow rate: 50 μl/min; k_(on) 6.68×10⁵ l/Ms; k_(off): 1.75×10⁻⁵ l/s; K_(D): 26 pM). FIG. 22C) SPR-based affinity determination (ProteOn XPR36) of 4G8 IgG-IL-10M1 to human IL-10R1 fitted globally to a 1:1 interaction model (chip: NLC; ligand: IL 10R1 (1600RU); analyte: FAP 4G8 IgG-IL-10M1 164 kDa; concentration range analyte: 50, 10, 2, 0.4, 0.08, 0 nM; association time: 180 s; dissociation time: 600 s; flow rate: 50 μl/min; k_(on): 3.64×10⁵ l/Ms; k_(off): 2.96×10⁻⁴ l/s; K_(D): 815 pM).

FIGS. 23A-C. Purification of FAP-targeted 4B9-based “1+1” IgG-IL-2 qm immunoconjugate. FIG. 23A) Elution profile of the combined Protein A affinity and size exclusion chromatography. FIG. 23B) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 23C) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (99.2% monomer content).

FIGS. 24A-C. Purification of FAP-targeted 28H1-based “1+1” IgG-IL-2 qm immunoconjugate. FIG. 24A) Elution profile of the combined Protein A affinity and size exclusion chromatography. FIG. 24B) Analytical SDS-PAGE (NuPAGE Novex Bis-Tris Mini Gel, Invitrogen, MOPS running buffer) of the final product. FIG. 24C) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (100% monomer content).

FIGS. 25A-C. Purification of FAP-targeted 4B9-based “1+1” IgG-IL-7 immunoconjugate. FIG. 25A) Elution profile of the combined Protein A affinity and size exclusion chromatography. FIG. 25B) Analytical capillary electrophoresis SDS (Caliper) of the final product. FIG. 25C) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (98.6% monomer content).

FIGS. 26A-D. Purification of FAP-targeted 4B9-based “1+1” IgG-IFN-α immunoconjugate. FIG. 26A) Elution profile of the Protein A affinity chromatography step. FIG. 26B) Elution profile of the size exclusion chromatography step. FIG. 26C) Analytical capillary electrophoresis SDS (Caliper) of the final product. FIG. 26D) Analytical size exclusion chromatography of the final product on a TSKgel G3000 SW XL column (92.8% monomer content).

FIG. 27. Induction of NK92 cell proliferation by FAP-targeted 4B9 “1+1” IgG-IL-2 qm and 28H1 “1+1” IgG-IL-2 wt immunoconjugates, compared to corresponding IgG-IL-2 constructs.

FIGS. 28A-B. Proliferation of PHA-activated (FIG. 28A) CD4 and (FIG. 28B) CD8 T cells induced by 4B9 “1+1” IgG-IL-7 and 4B9 “1+1” IgG-IL-2 qm immunoconjugates, compared to IgG-IL-2 qm and IgG-IL-2 wt constructs.

FIG. 29. Induction of Daudi cell proliferation by 4B9 “1+1” IgG-IFN-α, compared to Roferon A.

FIGS. 30A-B. Serum concentrations of IL-2 immunoconjugates after a single i.v. administration of FAP-targeted (FIG. 30A) and untargeted (FIG. 30B) IgG-IL-2 constructs comprising either wild-type (wt) or quadruple mutant (qm) IL-2.

FIG. 31. Tissue distribution of FAP-targeted 28H1 IgG-IL qm compared to unconjugated FAP-targeted 28H1 IgG and 4B9 IgG, as well as untargeted DP47GS IgG, 24 hours after i.v. injection.

FIG. 32. Binding of 28H1 IgG-IL-2 qm and 28H1 IgG-(IL-2 qm)₂ immunoconjugates to NK92 cells as determined by FACS.

FIGS. 33A-C. Proliferation of NK cells upon incubation with different FAP-targeted 28H1 IL-2 immunoconjugates or Proleukin for 4 (FIG. 33A), 5 (FIG. 33B) or 6 (FIG. 33C) days.

FIGS. 34A-C. Proliferation of CD4 T-cells upon incubation with different FAP-targeted 28H1 IL-2 immunoconjugates or Proleukin for 4 (FIG. 34A), 5 (FIG. 34B) or 6 (FIG. 34C) days.

FIGS. 35A-C. Proliferation of CD8 T-cells upon incubation with different FAP-targeted 28H1 IL-2 immunoconjugates or Proleukin for 4 (FIG. 35A), 5 (FIG. 35B) or 6 (FIG. 35C) days.

FIGS. 36A-B. Proliferation of pre-activated CD8 (FIG. 36A) and CD4 (FIG. 36B) T cells after six days incubation with different IL-2 immunoconjugates.

FIG. 37. Activation induced cell death of CD3⁺ T cells after six days incubation with different IL-2 immunoconjugates and overnight treatment with anti-Fas antibody.

FIGS. 38A-B. Serum concentrations of IL-2 immunoconjugates after a single i.v. administration of untargeted DP47GS IgG-IL-2 constructs comprising either wild-type (FIG. 38A) or quadruple mutant IL-2 (FIG. 38B).

FIG. 39. Binding of DP47GS IgG to different antigens. Binding was detected in an ELISA-based assay with the antigens captured on the plate. A human IgG1 antibody which exhibits unspecific binding to almost all of the captured antigens was used as positive control, blank samples did not contain any antibody.

FIGS. 40A-L. Binding of DP47GS IgG with or without LALA P329G mutation in the Fc domain to subsets of fresh (FIGS. 40A-D), PHA-L activated (FIGS. 40E-H) and re-stimulated (FIGS. 40I-L) human PBMCs, as determined by FACS analysis. Upper left panel: B cells (in FIG. 40A and FIG. 40E) or CD4⁺ T cells (in FIG. 40I); upper right panel: CD8⁺ T cells (in FIG. 40B, FIG. 40F and FIG. 40J); lower left panel (in FIG. 40C, FIG. 40G, and FIG. 40K): NK cells; lower right panel (in FIG. 40D, FIG. 40H, and FIG. 40L): CD14⁺ cells (monocytes/neutrophils).

DETAILED DESCRIPTION OF THE INVENTION Definitions

Terms are used herein as generally used in the art, unless otherwise defined in the following.

As used herein, the term “conjugate” refers to a fusion polypeptide molecule that includes one effector moiety and a further peptide molecule, particularly an immunoglobulin molecule.

As used herein, the term “immunoconjugate” refers to a fusion polypeptide molecule that includes one effector moiety, at least one antigen binding moiety and an Fc domain, provided that not more than one effector moiety is present. In certain embodiments, the immunoconjugate comprises one effector moiety, two antigen binding moieties, and an Fc domain. Particular immunoconjugates according to the invention essentially consist of one effector moiety, two antigen binding moieties, and an Fc domain, joined by one or more linker sequences. The antigen binding moiety and the effector moiety can be joined to the Fc domain by a variety of interactions and in a variety of configurations as described herein. In a particular embodiment, the two antigen binding moieties and the Fc domain are joined to each other in a configuration so as to form a full immunoglobulin molecule. An immunoconjugate as referred to herein, is a fusion protein, i.e. the components of the immunoconjugate are linked to each other by peptide-bonds, either directly or through linker peptides.

As used herein, the term “antigen binding moiety” refers to a polypeptide molecule that specifically binds to an antigenic determinant. In one embodiment, an antigen binding moiety is able to direct the entity to which it is attached (e.g. an effector moiety or a second antigen binding moiety) to a target site, for example to a specific type of tumor cell or tumor stroma bearing the antigenic determinant. Antigen binding moieties include antibodies and fragments thereof as further defined herein. Particular antigen binding moieties include an antigen binding domain of an antibody, comprising an antibody heavy chain variable region and an antibody light chain variable region. In certain embodiments, the antigen binding moieties may comprise antibody constant regions as further defined herein and known in the art. Useful heavy chain constant regions include any of the five isotypes: α, δ, ε, γ, or μ. Useful light chain constant regions include any of the two isotypes: κ and λ.

As used herein, the term “antigenic determinant” is synonymous with “antigen” and “epitope,” and refers to a site (e.g. a contiguous stretch of amino acids or a conformational configuration made up of different regions of non-contiguous amino acids) on a polypeptide macromolecule to which an antigen binding moiety binds, forming an antigen binding moiety-antigen complex.

Useful antigenic determinants can be found, for example, on the surfaces of tumor cells, on the surfaces of virus-infected cells, on the surfaces of other diseased cells, free in blood serum, and/or in the extracellular matrix (ECM). In a particular embodiment the antigenic determinant is a human antigen.

By “specifically binds” is meant that the binding is selective for the antigen and can be discriminated from unwanted or non-specific interactions. The ability of an antigen-binding moiety to bind to a specific antigenic determinant can be measured either through an enzyme-linked immunosorbent assay (ELISA) or other techniques familiar to one of skill in the art, e.g. surface plasmon resonance (SPR) technique (analyzed on a BIAcore instrument) (Liljeblad et al., Glyco J 17, 323-329 (2000)), and traditional binding assays (Heeley, Endocr Res 28, 217-229 (2002)). In one embodiment, the extent of binding of an antigen binding moiety to an unrelated protein is less than about 10% of the binding of the antigen binding moiety to the antigen as measured, e.g., by SPR. In certain embodiments, an antigen binding moiety that binds to the antigen, or an immunoconjugate comprising that antigen binding moiety, has a dissociation constant (K_(D)) of ≤1 μM, ≤100 nM, ≤10 nM, ≤1 nM, ≤0.1 nM, ≤0.01 nM, or ≤0.001 nM (e.g. 10⁻⁸M or less, e.g. from 10⁻⁸M to 10⁻¹³M, e.g., from 10⁻⁹M to 10⁻¹³ M).

“Affinity” refers to the strength of the sum total of non-covalent interactions between a single binding site of a molecule (e.g., a receptor) and its binding partner (e.g., a ligand). Unless indicated otherwise, as used herein, “binding affinity” refers to intrinsic binding affinity which reflects a 1:1 interaction between members of a binding pair (e.g., receptor and a ligand). The affinity of a molecule X for its partner Y can generally be represented by the dissociation constant (K_(D)), which is the ratio of dissociation and association rate constants (k_(off) and k_(on), respectively). Thus, equivalent affinities may comprise different rate constants, as long as the ratio of the rate constants remains the same. Affinity can be measured by well established methods known in the art, including those described herein. A particular method for measuring affinity is Surface Plasmon Resonance (SPR).

“Reduced binding”, for example reduced binding to an Fc receptor or to CD25, refers to a decrease in affinity for the respective interaction, as measured for example by SPR. For clarity the term includes also reduction of the affinity to zero (or below the detection limit of the analytic method), i.e. complete abolishment of the interaction. Conversely, “increased binding” refers to an increase in binding affinity for the respective interaction.

As used herein, the terms “first” and “second” with respect to antigen-binding moieties etc., are used for convenience of distinguishing when there is more than one of each type of moiety. Use of these terms is not intended to confer a specific order or orientation of the immunoconjugate unless explicitly so stated.

As used herein, the term “effector moiety” refers to a polypeptide, e.g., a protein or glycoprotein, that influences cellular activity, for example, through signal transduction or other cellular pathways. Accordingly, the effector moiety of the invention can be associated with receptor-mediated signaling that transmits a signal from outside the cell membrane to modulate a response in a cell bearing one or more receptors for the effector moiety. In one embodiment, an effector moiety can elicit a cytotoxic response in cells bearing one or more receptors for the effector moiety. In another embodiment, an effector moiety can elicit a proliferative response in cells bearing one or more receptors for the effector moiety. In another embodiment, an effector moiety can elicit differentiation in cells bearing receptors for the effector moiety. In another embodiment, an effector moiety can alter expression (i.e. upregulate or downregulate) of an endogenous cellular protein in cells bearing receptors for the effector moiety. Non-limiting examples of effector moieties include cytokines, growth factors, hormones, enzymes, substrates, and cofactors. The effector moiety can be associated with an antigen-binding moiety or an Fc domain in a variety of configurations to form an immunoconjugate.

As used herein, the term “cytokine” refers to a molecule that mediates and/or regulates a biological or cellular function or process (e.g. immunity, inflammation, and hematopoiesis). The term “cytokine” as used herein includes “lymphokines,” “chemokines,” “monokines,” and “interleukins”. Examples of useful cytokines include, but are not limited to, GM-CSF, IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IFN-α, IFN-β, IFN-γ, MIP-1α, MIP-1β, TGF-β, TNF-α, and TNF-β. Particular cytokines are IL-2, IL-7, IL-10, IL-12, IL-15, IFN-α and IFN-γ. In particular embodiments the cytokine is a human cytokine. The term “cytokine” as used herein is meant to also include cytokine variants comprising one or more amino acid mutations in the amino acid sequences of the corresponding wild-type cytokine, such as for example the IL-2 variants described in Sauvé et al., Proc Natl Acad Sci USA 88, 4636-40 (1991); Hu et al., Blood 101, 4853-4861 (2003) and US Pat. Publ. No. 2003/0124678; Shanafelt et al., Nature Biotechnol 18, 1197-1202 (2000); Heaton et al., Cancer Res 53, 2597-602 (1993) and U.S. Pat. No. 5,229,109; US Pat. Publ. No. 2007/0036752; WO 2008/0034473; WO 2009/061853; or PCT patent application no. PCT/EP2012/051991. Further cytokine variants, for example variants of IL-15, are described herein. In certain embodiments cytokines have been mutated to eliminate glycosylation.

As used herein, the term “single-chain” refers to a molecule comprising amino acid monomers linearly linked by peptide bonds. In one embodiment, the effector moiety is a single-chain effector moiety. Non-limiting examples of single-chain effector moieties include cytokines, growth factors, hormones, enzymes, substrates, and cofactors. When the effector moiety is a cytokine and the cytokine of interest is normally found as a multimer in nature, each subunit of the multimeric cytokine is sequentially encoded by the single-chain of the effector moiety. Accordingly, non-limiting examples of useful single-chain effector moieties include GM-CSF, IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-15, IFN-α, IFN-β, IFN-γ, MIP-1α, MIP-1β, TGF-β, TNF-α, and TNF-β.

As used herein, the term “control effector moiety” refers to an unconjugated effector moiety. For example, when comparing an IL-2 immunoconjugate as described herein with a control effector moiety, the control effector moiety is free, unconjugated IL-2. Likewise, e.g., when comparing an IL-12 immunoconjugate with a control effector moiety, the control effector moiety is free, unconjugated IL-12 (e.g. existing as a heterodimeric protein wherein the p40 and p35 subunits share only disulfide bond(s)).

As used herein, the term “effector moiety receptor” refers to a polypeptide molecule capable of binding specifically to an effector moiety. For example, where IL-2 is the effector moiety, the effector moiety receptor that binds to an IL-2 molecule (e.g. an immunoconjugate comprising IL-2) is the IL-2 receptor. Similarly, e.g., where IL-12 is the effector moiety of an immunoconjugate, the effector moiety receptor is the IL-12 receptor. Where an effector moiety specifically binds to more than one receptor, all receptors that specifically bind to the effector moiety are “effector moiety receptors” for that effector moiety.

The term “immunoglobulin molecule” refers to a protein having the structure of a naturally occurring antibody. For example, immunoglobulins of the IgG class are heterotetrameric glycoproteins of about 150,000 daltons, composed of two light chains and two heavy chains that are disulfide-bonded. From N- to C-terminus, each heavy chain has a variable region (VH), also called a variable heavy domain or a heavy chain variable domain, followed by three constant domains (CH1, CH2, and CH3), also called a heavy chain constant region. Similarly, from N- to C-terminus, each light chain has a variable region (VL), also called a variable light domain or a light chain variable domain, followed by a constant light (CL) domain, also called a light chain constant region. The heavy chain of an immunoglobulin may be assigned to one of five types, called α (IgA), δ (IgD), ε (IgE), γ (IgG), or μ (IgM), some of which may be further divided into subtypes, e.g. γ₁ (IgG₁), γ₂ (IgG₂), γ₃ (IgG₃), γ₄ (IgG₄), α₁ (IgA₁) and α₂ (IgA₂). The light chain of an immunoglobulin may be assigned to one of two types, called kappa (κ) and lambda (λ), based on the amino acid sequence of its constant domain. An immunoglobulin essentially consists of two Fab molecules and an Fc domain, linked via the immunoglobulin hinge region.

The term “antibody” herein is used in the broadest sense and encompasses various antibody structures, including but not limited to monoclonal antibodies, polyclonal antibodies, and antibody fragments so long as they exhibit the desired antigen-binding activity.

An “antibody fragment” refers to a molecule other than an intact antibody that comprises a portion of an intact antibody that binds the antigen to which the intact antibody binds. Examples of antibody fragments include but are not limited to Fv, Fab, Fab′, Fab′-SH, F(ab′)₂, diabodies, linear antibodies, single-chain antibody molecules (e.g. scFv), and single-domain antibodies. For a review of certain antibody fragments, see Hudson et al., Nat Med 9, 129-134 (2003). For a review of scFv fragments, see e.g. Plückthun, in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994); see also WO 93/16185; and U.S. Pat. Nos. 5,571,894 and 5,587,458. For discussion of Fab and F(ab′)₂ fragments comprising salvage receptor binding epitope residues and having increased in vivo half-life, see U.S. Pat. No. 5,869,046. Diabodies are antibody fragments with two antigen-binding sites that may be bivalent or bispecific. See, for example, EP 404,097; WO 1993/01161; Hudson et al., Nat Med 9, 129-134 (2003); and Hollinger et al., Proc Natl Acad Sci USA 90, 6444-6448 (1993). Triabodies and tetrabodies are also described in Hudson et al., Nat Med 9, 129-134 (2003). Single-domain antibodies are antibody fragments comprising all or a portion of the heavy chain variable domain or all or a portion of the light chain variable domain of an antibody. In certain embodiments, a single-domain antibody is a human single-domain antibody (Domantis, Inc., Waltham, Mass.; see e.g. U.S. Pat. No. 6,248,516 B1). Antibody fragments can be made by various techniques, including but not limited to proteolytic digestion of an intact antibody as well as production by recombinant host cells (e.g. E. coli or phage), as described herein.

The term “antigen binding domain” refers to the part of an antibody that comprises the area which specifically binds to and is complementary to part or all of an antigen. An antigen binding domain may be provided by, for example, one or more antibody variable domains (also called antibody variable regions). Particularly, an antigen binding domain comprises an antibody light chain variable region (VL) and an antibody heavy chain variable region (VH).

The term “variable region” or “variable domain” refers to the domain of an antibody heavy or light chain that is involved in binding the antibody to antigen. The variable domains of the heavy chain and light chain (VH and VL, respectively) of a native antibody generally have similar structures, with each domain comprising four conserved framework regions (FRs) and three hypervariable regions (HVRs). See, e.g., Kindt et al., Kuby Immunology, 6^(th) ed., W.H. Freeman and Co., page 91 (2007). A single VH or VL domain may be sufficient to confer antigen-binding specificity.

The term “hypervariable region” or “HVR”, as used herein, refers to each of the regions of an antibody variable domain which are hypervariable in sequence and/or form structurally defined loops (“hypervariable loops”). Generally, native four-chain antibodies comprise six HVRs; three in the VH (H1, H2, H3), and three in the VL (L1, L2, L3). HVRs generally comprise amino acid residues from the hypervariable loops and/or from the complementarity determining regions (CDRs), the latter being of highest sequence variability and/or involved in antigen recognition.

With the exception of CDR1 in VH, CDRs generally comprise the amino acid residues that form the hypervariable loops. Hypervariable regions (HVRs) are also referred to as “complementarity determining regions” (CDRs), and these terms are used herein interchangeably in reference to portions of the variable region that form the antigen binding regions. This particular region has been described by Kabat et al., U.S. Dept. of Health and Human Services, Sequences of Proteins of Immunological Interest (1983) and by Chothia et al., J Mol Biol 196:901-917 (1987), where the definitions include overlapping or subsets of amino acid residues when compared against each other. Nevertheless, application of either definition to refer to a CDR of an antibody or variants thereof is intended to be within the scope of the term as defined and used herein. The appropriate amino acid residues which encompass the CDRs as defined by each of the above cited references are set forth below in Table 1 as a comparison. The exact residue numbers which encompass a particular CDR will vary depending on the sequence and size of the CDR. Those skilled in the art can routinely determine which residues comprise a particular CDR given the variable region amino acid sequence of the antibody.

TABLE 1 CDR Definitions¹ CDR Kabat Chothia AbM² V_(H) CDR1 31-35 26-32 26-35 V_(H) CDR2 50-65 52-58 50-58 V_(H) CDR3 95-102 95-102 95-102 V_(L) CDR1 24-34 26-32 24-34 V_(L) CDR2 50-56 50-52 50-56 V_(L) CDR3 89-97 91-96 89-97 ¹Numbering of all CDR definitions in Table 1 is according to the numbering conventions set forth by Kabat et al. (see below). ²“AbM” with a lowercase “b” as used in Table 1 refers to the CDRs as defined by Oxford Molecular's “AbM” antibody modeling software.

Kabat et al. also defined a numbering system for variable region sequences that is applicable to any antibody. One of ordinary skill in the art can unambiguously assign this system of “Kabat numbering” to any variable region sequence, without reliance on any experimental data beyond the sequence itself. As used herein, “Kabat numbering” refers to the numbering system set forth by Kabat et al., U.S. Dept. of Health and Human Services, “Sequence of Proteins of Immunological Interest” (1983). Unless otherwise specified, references to the numbering of specific amino acid residue positions in an antibody variable region are according to the Kabat numbering system.

The polypeptide sequences of the sequence listing (i.e., SEQ ID NOs 23, 25, 27, 29, 31, etc.) are not numbered according to the Kabat numbering system. However, it is well within the ordinary skill of one in the art to convert the numbering of the sequences of the Sequence Listing to Kabat numbering.

“Framework” or “FR” refers to variable domain residues other than hypervariable region (HVR) residues. The FR of a variable domain generally consists of four FR domains: FR1, FR2, FR3, and FR4. Accordingly, the HVR and FR sequences generally appear in the following sequence in VH (or VL): FR1-H1(L1)-FR2-H2(L2)-FR3-H3(L3)-FR4.

The “class” of an antibody or immunoglobulin refers to the type of constant domain or constant region possessed by its heavy chain. There are five major classes of antibodies: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), e.g., IgG₁, IgG₂, IgG₃, IgG₄, IgA₁, and IgA₂. The heavy chain constant domains that correspond to the different classes of immunoglobulins are called α, δ, ε, γ, and μ, respectively.

The term “Fc domain” or “Fc region” herein is used to define a C-terminal region of an immunoglobulin heavy chain that contains at least a portion of the constant region. The term includes native sequence Fc regions and variant Fc regions. Although the boundaries of the Fc region of an IgG heavy chain might vary slightly, the human IgG heavy chain Fc region is usually defined to extend from Cys226, or from Pro230, to the carboxyl-terminus of the heavy chain. However, the C-terminal lysine (Lys447) of the Fc region may or may not be present. Unless otherwise specified herein, numbering of amino acid residues in the Fc region or constant region is according to the EU numbering system, also called the EU index, as described in Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md., 1991. A “subunit” of an Fc domain as used herein refers to one of the two polypeptides forming the dimeric Fc domain, i.e. a polypeptide comprising C-terminal constant regions of an immunoglobulin heavy chain, capable of stable self-association. For example, a subunit of an IgG Fc domain comprises an IgG CH2 and an IgG CH3 constant domain.

A “modification promoting heterodimerization” is a manipulation of the peptide backbone or the post-translational modifications of a polypeptide that reduces or prevents the association of the polypeptide with an identical polypeptide to form a homodimer. A modification promoting heterodimerization as used herein particularly includes separate modifications made to each of two polypeptides desired to form a dimer, wherein the modifications are complementary to each other so as to promote association of the two polypeptides. For example, a modification promoting heterodimerization may alter the structure or charge of one or both of the polypeptides desired to form a dimer so as to make their association sterically or electrostatically favorable, respectively. Heterodimerization occurs between two non-identical polypeptides, such as two subunits of an Fc domain wherein further immunoconjugate components fused to each of the subunits (e.g. antigen binding moiety, effector moiety) are not the same. In the immunoconjugates according to the present invention, the modification promoting heterodimerization is in the Fc domain. In some embodiments the modification promoting heterodimerziation comprises an amino acid mutation, specifically an amino acid substitution. In a particular embodiment, the modification promoting heterodimerization comprises a separate amino acid mutation, specifically an amino acid substitution, in each of the two subunits of the Fc domain.

The term “effector functions” refers to those biological activities attributable to the Fc region of an antibody, which vary with the antibody isotype. Examples of antibody effector functions include: C1q binding and complement dependent cytotoxicity (CDC), Fc receptor binding, antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), cytokine secretion, immune complex-mediated antigen uptake by antigen presenting cells, down regulation of cell surface receptors (e.g. B cell receptor), and B cell activation.

As used herein, the terms “engineer, engineered, engineering”, are considered to include any manipulation of the peptide backbone or the post-translational modifications of a naturally occurring or recombinant polypeptide or fragment thereof. Engineering includes modifications of the amino acid sequence, of the glycosylation pattern, or of the side chain group of individual amino acids, as well as combinations of these approaches. “Engineering”, particularly with the prefix “glyco-”, as well as the term “glycosylation engineering” includes metabolic engineering of the glycosylation machinery of a cell, including genetic manipulations of the oligosaccharide synthesis pathways to achieve altered glycosylation of glycoproteins expressed in cells. Furthermore, glycosylation engineering includes the effects of mutations and cell environment on glycosylation. In one embodiment, the glycosylation engineering is an alteration in glycosyltransferase activity. In a particular embodiment, the engineering results in altered glucosaminyltransferase activity and/or fucosyltransferase activity. Glycosylation engineering can be used to obtain a “host cell having increased GnTIII activity”, a “host cell having increased ManII activity”, or a “host cell having decreased α(1,6) fucosyltransferase activity”.

The term “amino acid mutation” as used herein is meant to encompass amino acid substitutions, deletions, insertions, and modifications. Any combination of substitution, deletion, insertion, and modification can be made to arrive at the final construct, provided that the final construct possesses the desired characteristics, e.g., reduced binding to an Fc receptor, or reduced binding to CD25. Amino acid sequence deletions and insertions include amino- and/or carboxy-terminal deletions and insertions of amino acids. Particular amino acid mutations are amino acid substitutions. For the purpose of altering e.g. the binding characteristics of an Fc region or a cytokine such as IL-2, non-conservative amino acid substitutions, i.e. replacing one amino acid with another amino acid having different structural and/or chemical properties, are particularly preferred. Amino acid substitutions include replacement by non-naturally occurring amino acids or by naturally occurring amino acid derivatives of the twenty standard amino acids (e.g. 4-hydroxyproline, 3-methylhistidine, ornithine, homoserine, 5-hydroxylysine). Amino acid mutations can be generated using genetic or chemical methods well known in the art. Genetic methods may include site-directed mutagenesis, PCR, gene synthesis and the like. It is contemplated that methods of altering the side chain group of an amino acid by methods other than genetic engineering, such as chemical modification, may also be useful. Various designations may be used herein to indicate the same amino acid mutation. For example, a substitution from proline at position 329 of the Fc domain to glycine can be indicated as 329G, G329, G₃₂₉, P329G, or Pro329Gly.

As used herein, term “polypeptide” refers to a molecule composed of monomers (amino acids) linearly linked by amide bonds (also known as peptide bonds). The term “polypeptide” refers to any chain of two or more amino acids, and does not refer to a specific length of the product. Thus, peptides, dipeptides, tripeptides, oligopeptides, “protein,” “amino acid chain,” or any other term used to refer to a chain of two or more amino acids, are included within the definition of “polypeptide,” and the term “polypeptide” may be used instead of, or interchangeably with any of these terms. The term “polypeptide” is also intended to refer to the products of post-expression modifications of the polypeptide, including without limitation glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting/blocking groups, proteolytic cleavage, or modification by non-naturally occurring amino acids. A polypeptide may be derived from a natural biological source or produced by recombinant technology, but is not necessarily translated from a designated nucleic acid sequence. It may be generated in any manner, including by chemical synthesis. A polypeptide of the invention may be of a size of about 3 or more, 5 or more, 10 or more, 20 or more, 25 or more, 50 or more, 75 or more, 100 or more, 200 or more, 500 or more, 1,000 or more, or 2,000 or more amino acids. Polypeptides may have a defined three-dimensional structure, although they do not necessarily have such structure. Polypeptides with a defined three-dimensional structure are referred to as folded, and polypeptides which do not possess a defined three-dimensional structure, but rather can adopt a large number of different conformations, and are referred to as unfolded.

By an “isolated” polypeptide or a variant, or derivative thereof is intended a polypeptide that is not in its natural milieu. No particular level of purification is required. For example, an isolated polypeptide can be removed from its native or natural environment. Recombinantly produced polypeptides and proteins expressed in host cells are considered isolated for the purpose of the invention, as are native or recombinant polypeptides which have been separated, fractionated, or partially or substantially purified by any suitable technique.

“Percent (%) amino acid sequence identity” with respect to a reference polypeptide sequence is defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the reference polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for aligning sequences, including any algorithms needed to achieve maximal alignment over the full length of the sequences being compared. For purposes herein, however, % amino acid sequence identity values are generated using the sequence comparison computer program ALIGN-2. The ALIGN-2 sequence comparison computer program was authored by Genentech, Inc., and the source code has been filed with user documentation in the U.S. Copyright Office, Washington D.C., 20559, where it is registered under U.S. Copyright Registration No. TXU510087. The ALIGN-2 program is publicly available from Genentech, Inc., South San Francisco, Calif., or may be compiled from the source code. The ALIGN-2 program should be compiled for use on a UNIX operating system, including digital UNIX V4.0D. All sequence comparison parameters are set by the ALIGN-2 program and do not vary. In situations where ALIGN-2 is employed for amino acid sequence comparisons, the % amino acid sequence identity of a given amino acid sequence A to, with, or against a given amino acid sequence B (which can alternatively be phrased as a given amino acid sequence A that has or comprises a certain % amino acid sequence identity to, with, or against a given amino acid sequence B) is calculated as follows: 100 times the fraction X/Y where X is the number of amino acid residues scored as identical matches by the sequence alignment program ALIGN-2 in that program's alignment of A and B, and where Y is the total number of amino acid residues in B. It will be appreciated that where the length of amino acid sequence A is not equal to the length of amino acid sequence B, the % amino acid sequence identity of A to B will not equal the % amino acid sequence identity of B to A. Unless specifically stated otherwise, all % amino acid sequence identity values used herein are obtained as described in the immediately preceding paragraph using the ALIGN-2 computer program.

The term “polynucleotide” refers to an isolated nucleic acid molecule or construct, e.g. messenger RNA (mRNA), virally-derived RNA, or plasmid DNA (pDNA). A polynucleotide may comprise a conventional phosphodiester bond or a non-conventional bond (e.g. an amide bond, such as found in peptide nucleic acids (PNA). The term “nucleic acid molecule” refers to any one or more nucleic acid segments, e.g. DNA or RNA fragments, present in a polynucleotide.

By “isolated” nucleic acid molecule or polynucleotide is intended a nucleic acid molecule, DNA or RNA, which has been removed from its native environment. For example, a recombinant polynucleotide encoding a therapeutic polypeptide contained in a vector is considered isolated for the purposes of the present invention. Further examples of an isolated polynucleotide include recombinant polynucleotides maintained in heterologous host cells or purified (partially or substantially) polynucleotides in solution. An isolated polynucleotide includes a polynucleotide molecule contained in cells that ordinarily contain the polynucleotide molecule, but the polynucleotide molecule is present extrachromosomally or at a chromosomal location that is different from its natural chromosomal location. Isolated RNA molecules include in vivo or in vitro RNA transcripts of the present invention, as well as positive and negative strand forms, and double-stranded forms. Isolated polynucleotides or nucleic acids according to the present invention further include such molecules produced synthetically. In addition, a polynucleotide or a nucleic acid may be or may include a regulatory element such as a promoter, ribosome binding site, or a transcription terminator.

By a nucleic acid or polynucleotide having a nucleotide sequence at least, for example, 95% “identical” to a reference nucleotide sequence of the present invention, it is intended that the nucleotide sequence of the polynucleotide is identical to the reference sequence except that the polynucleotide sequence may include up to five point mutations per each 100 nucleotides of the reference nucleotide sequence. In other words, to obtain a polynucleotide having a nucleotide sequence at least 95% identical to a reference nucleotide sequence, up to 5% of the nucleotides in the reference sequence may be deleted or substituted with another nucleotide, or a number of nucleotides up to 5% of the total nucleotides in the reference sequence may be inserted into the reference sequence. These alterations of the reference sequence may occur at the 5′ or 3′ terminal positions of the reference nucleotide sequence or anywhere between those terminal positions, interspersed either individually among residues in the reference sequence or in one or more contiguous groups within the reference sequence. As a practical matter, whether any particular polynucleotide sequence is at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to a nucleotide sequence of the present invention can be determined conventionally using known computer programs, such as the ones discussed above for polypeptides (e.g. ALIGN-2).

The term “expression cassette” refers to a polynucleotide generated recombinantly or synthetically, with a series of specified nucleic acid elements that permit transcription of a particular nucleic acid in a target cell. The recombinant expression cassette can be incorporated into a plasmid, chromosome, mitochondrial DNA, plastid DNA, virus, or nucleic acid fragment. Typically, the recombinant expression cassette portion of an expression vector includes, among other sequences, a nucleic acid sequence to be transcribed and a promoter. In certain embodiments, the expression cassette of the invention comprises polynucleotide sequences that encode immunoconjugates of the invention or fragments thereof.

The term “vector” or “expression vector” is synonymous with “expression construct” and refers to a DNA molecule that is used to introduce and direct the expression of a specific gene to which it is operably associated in a target cell. The term includes the vector as a self-replicating nucleic acid structure as well as the vector incorporated into the genome of a host cell into which it has been introduced. The expression vector of the present invention comprises an expression cassette. Expression vectors allow transcription of large amounts of stable mRNA. Once the expression vector is inside the target cell, the ribonucleic acid molecule or protein that is encoded by the gene is produced by the cellular transcription and/or translation machinery. In one embodiment, the expression vector of the invention comprises an expression cassette that comprises polynucleotide sequences that encode immunoconjugates of the invention or fragments thereof.

The term “artificial” refers to a synthetic, or non-host cell derived composition, e.g. a chemically-synthesized oligonucleotide.

The terms “host cell”, “host cell line,” and “host cell culture” are used interchangeably and refer to cells into which exogenous nucleic acid has been introduced, including the progeny of such cells. Host cells include “transformants” and “transformed cells,” which include the primary transformed cell and progeny derived therefrom without regard to the number of passages.

Progeny may not be completely identical in nucleic acid content to a parent cell, but may contain mutations. Mutant progeny that have the same function or biological activity as screened or selected for in the originally transformed cell are included herein. A host cell is any type of cellular system that can be used to generate the immunoconjugates used for the present invention. In one embodiment, the host cell is engineered to allow the production of an immunoconjugate with modified oligosaccharides in its Fc region. In certain embodiments, the host cells have been manipulated to express increased levels of one or more polypeptides having β(1,4)-N-acetylglucosaminyltransferase III (GnTIII) activity. In certain embodiments the host cells have been further manipulated to express increased levels of one or more polypeptides having α-mannosidase II (ManII) activity. Host cells include cultured cells, e.g. mammalian cultured cells, such as CHO cells, BHK cells, NS0 cells, SP2/0 cells, YO myeloma cells, P3X63 mouse myeloma cells, PER cells, PER.C6 cells or hybridoma cells, yeast cells, insect cells, and plant cells, to name only a few, but also cells comprised within a transgenic animal, transgenic plant or cultured plant or animal tissue.

As used herein, the term “polypeptide having GnTIII activity” refers to polypeptides that are able to catalyze the addition of a N-acetylglucosamine (GlcNAc) residue in β-1,4 linkage to the β-linked mannoside of the trimannosyl core of N-linked oligosaccharides. This includes fusion polypeptides exhibiting enzymatic activity similar to, but not necessarily identical to, an activity of β(1,4)-N-acetylglucosaminyltransferase III, also known as β-1,4-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyl-transferase (EC 2.4.1.144), according to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB), as measured in a particular biological assay, with or without dose dependency. In the case where dose dependency does exist, it need not be identical to that of GnTIII, but rather substantially similar to the dose-dependency in a given activity as compared to the GnTIII (i.e. the candidate polypeptide will exhibit greater activity or not more than about 25-fold less and, preferably, not more than about ten-fold less activity, and most preferably, not more than about three-fold less activity relative to the GnTIII). In certain embodiments the polypeptide having GnTIII activity is a fusion polypeptide comprising the catalytic domain of GnTIII and the Golgi localization domain of a heterologous Golgi resident polypeptide. Particularly, the Golgi localization domain is the localization domain of mannosidase II or GnTI, most particularly the localization domain of mannosidase II. Alternatively, the Golgi localization domain is selected from the group consisting of: the localization domain of mannosidase I, the localization domain of GnTII, and the localization domain of α1,6 core fucosyltransferase. Methods for generating such fusion polypeptides and using them to produce antibodies with increased effector functions are disclosed in WO 2004/065540, U.S. Provisional Pat. Appl. No. 60/495,142 and U.S. Pat. Appl. Publ. No. 2004/0241817, the entire contents of which are expressly incorporated herein by reference.

As used herein, the term “Golgi localization domain” refers to the amino acid sequence of a Golgi resident polypeptide which is responsible for anchoring the polypeptide to a location within the Golgi complex. Generally, localization domains comprise amino terminal “tails” of an enzyme.

As used herein, the term “polypeptide having ManII activity” refers to polypeptides that are able to catalyze the hydrolysis of the terminal 1,3- and 1,6-linked α-D-mannose residues in the branched GlcNAcMan₅GlcNAc₂ mannose intermediate of N-linked oligosaccharides. This includes polypeptides exhibiting enzymatic activity similar to, but not necessarily identical to, an activity of Golgi α-mannosidase II, also known as mannosyl oligosaccharide 1,3-1,6-α-mannosidase II (EC 3.2.1.114), according to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB).

An “activating Fc receptor” is an Fc receptor that following engagement by an Fc region of an antibody (or immunoconjugate) elicits signaling events that stimulate the receptor-bearing cell to perform effector functions. Activating Fc receptors include FcγRIIIa (CD16a), FcγRI (CD64), FcγRIIa (CD32), and FcαRI (CD89).

Antibody-dependent cell-mediated cytotoxicity (ADCC) is an immune mechanism leading to the lysis of antibody-coated target cells by immune effector cells. The target cells are cells to which antibodies, immunoconjugates or fragments thereof comprising an Fc region specifically bind, generally via the protein part that is N-terminal to the Fc region. As used herein, the term “increased ADCC” is defined as either an increase in the number of target cells that are lysed in a given time, at a given concentration of immunoconjugate in the medium surrounding the target cells, by the mechanism of ADCC defined above, and/or a reduction in the concentration of immunoconjugate, in the medium surrounding the target cells, required to achieve the lysis of a given number of target cells in a given time, by the mechanism of ADCC. The increase in ADCC is relative to the ADCC mediated by the same immunoconjugate produced by the same type of host cells, using the same standard production, purification, formulation and storage methods (which are known to those skilled in the art), but that has not been engineered. For example the increase in ADCC mediated by an immunoconjugate produced by host cells engineered to have an altered pattern of glycosylation (e.g. to express the glycosyltransferase, GnTIII, or other glycosyltransferases) by the methods described herein, is relative to the ADCC mediated by the same immunoconjugate produced by the same type of non-engineered host cells.

By “immunoconjugate having increased antibody dependent cell-mediated cytotoxicity (ADCC)” is meant an immunoconjugate having increased ADCC as determined by any suitable method known to those of ordinary skill in the art. One accepted in vitro ADCC assay is as follows:

-   -   1) the assay uses target cells that are known to express the         target antigen recognized by the antigen binding moiety of the         immunoconjugate;     -   2) the assay uses human peripheral blood mononuclear cells         (PBMCs), isolated from blood of a randomly chosen healthy donor,         as effector cells;     -   3) the assay is carried out according to following protocol:     -   i) the PBMCs are isolated using standard density centrifugation         procedures and are suspended at 5×10⁶ cells/ml in RPMI cell         culture medium;     -   ii) the target cells are grown by standard tissue culture         methods, harvested from the exponential growth phase with a         viability higher than 90%, washed in RPMI cell culture medium,         labeled with 100 micro-Curies of ⁵¹Cr, washed twice with cell         culture medium, and resuspended in cell culture medium at a         density of 10⁵ cells/ml;     -   iii) 100 microliters of the final target cell suspension above         are transferred to each well of a 96-well microtiter plate;     -   iv) the immunoconjugate is serially-diluted from 4000 ng/ml to         0.04 ng/ml in cell culture medium and 50 microliters of the         resulting immunoconjugate solutions are added to the target         cells in the 96-well microtiter plate, testing in triplicate         various immunoconjugate concentrations covering the whole         concentration range above;     -   v) for the maximum release (MR) controls, 3 additional wells in         the plate containing the labeled target cells, receive 50         microliters of a 2% (V/V) aqueous solution of non-ionic         detergent (Nonidet, Sigma, St. Louis), instead of the         immunoconjugate solution (point iv above);     -   vi) for the spontaneous release (SR) controls, 3 additional         wells in the plate containing the labeled target cells, receive         50 microliters of RPMI cell culture medium instead of the         immunoconjugate solution (point iv above);     -   vii) the 96-well microtiter plate is then centrifuged at 50×g         for 1 minute and incubated for 1 hour at 4° C.;     -   viii) 50 microliters of the PBMC suspension (point i above) are         added to each well to yield an effector:target cell ratio of         25:1 and the plates are placed in an incubator under 5% CO₂         atmosphere at 37° C. for 4 hours;     -   ix) the cell-free supernatant from each well is harvested and         the experimentally released radioactivity (ER) is quantified         using a gamma counter;     -   x) the percentage of specific lysis is calculated for each         immunoconjugate concentration according to the formula         (ER−MR)/(MR−SR)×100, where ER is the average radioactivity         quantified (see point ix above) for that immunoconjugate         concentration, MR is the average radioactivity quantified (see         point ix above) for the MR controls (see point v above), and SR         is the average radioactivity quantified (see point ix above) for         the SR controls (see point vi above);     -   4) “increased ADCC” is defined as either an increase in the         maximum percentage of specific lysis observed within the         immunoconjugate concentration range tested above, and/or a         reduction in the concentration of immunoconjugate required to         achieve one half of the maximum percentage of specific lysis         observed within the immunoconjugate concentration range tested         above. The increase in ADCC is relative to the ADCC, measured         with the above assay, mediated by the same immunoconjugate,         produced by the same type of host cells, using the same standard         production, purification, formulation and storage methods, which         are known to those skilled in the art, but that has not been         engineered.

An “effective amount” of an agent refers to the amount that is necessary to result in a physiological change in the cell or tissue to which it is administered.

A “therapeutically effective amount” of an agent, e.g. a pharmaceutical composition, refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic or prophylactic result. A therapeutically effective amount of an agent for example eliminates, decreases, delays, minimizes or prevents adverse effects of a disease.

An “individual” or “subject” is a mammal. Mammals include, but are not limited to, domesticated animals (e.g. cows, sheep, cats, dogs, and horses), primates (e.g. humans and non-human primates such as monkeys), rabbits, and rodents (e.g. mice and rats). Particularly, the individual or subject is a human.

The term “pharmaceutical composition” refers to a preparation which is in such form as to permit the biological activity of an active ingredient contained therein to be effective, and which contains no additional components which are unacceptably toxic to a subject to which the formulation would be administered.

A “pharmaceutically acceptable carrier” refers to an ingredient in a pharmaceutical composition, other than an active ingredient, which is nontoxic to a subject. A pharmaceutically acceptable carrier includes, but is not limited to, a buffer, excipient, stabilizer, or preservative.

As used herein, “treatment” (and grammatical variations thereof such as “treat” or “treating”) refers to clinical intervention in an attempt to alter the natural course of a disease in the individual being treated, and can be performed either for prophylaxis or during the course of clinical pathology. Desirable effects of treatment include, but are not limited to, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, preventing metastasis, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis. In some embodiments, immunoconjugates of the invention are used to delay development of a disease or to slow the progression of a disease.

The term “package insert” is used to refer to instructions customarily included in commercial packages of therapeutic products, that contain information about the indications, usage, dosage, administration, combination therapy, contraindications and/or warnings concerning the use of such therapeutic products.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In a first aspect the invention provides an immunoconjugate comprising a first antigen binding moiety, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. The absence of further effector moieties may reduce targeting of the immunoconjugate to sites where the respective effector moiety receptor is presented, thereby improving targeting to and accumulation at sites where the actual target antigen of the immunoconjugate, which is recognized by the antigen binding moiety, is presented. Furthermore, the absence of an avidity effect for the respective effector moiety receptor can reduce activation of effector moiety receptor-positive cells in peripheral blood upon intravenous administration of the immunoconjugate. Furthermore, the serum half-life of immunoconjugates comprising only a single effector moiety appears to be longer as compared to immunoconjugates comprising two or more effector moieties.

Immunoconjugate Formats

The components of the immunoconjugate can be fused to each other in a variety of configurations. Exemplary configurations are depicted in FIGS. 2A-C. In one embodiment the effector moiety is fused to the amino- or carboxy-terminal amino acid of one of the two subunits of the Fc domain. In one embodiment the effector moiety is fused to the carboxy-terminal amino acid of one of the two subunits of the Fc domain. The effector moiety may be fused to the Fc domain directly or through a linker peptide, comprising one or more amino acids, typically about 2-20 amino acids. Linker peptides are known in the art or are described herein. Suitable, non-immunogenic linker peptides include, for example, (G₄S)_(n), (SG₄)_(n) or G₄(SG₄)_(n) linker peptides. “n” is generally a number between 1 and 10, typically between 2 and 4. Alternatively, where the effector moiety is linked to the N-terminus of an Fc domain subunit, it may be linked via an immunoglobulin hinge region or a portion thereof, with or without an additional linker peptide.

Similarly, the first antigen binding moiety can be fused to the amino- or carboxy-terminal amino acid of one of the two subunits of the Fc domain. In one embodiment the first antigen binding moiety is fused to the amino-terminal amino acid of one of the two subunits of the Fc domain.

The first antigen binding moiety may be fused to the Fc domain directly or through a linker peptide. In a particular embodiment the first antigen binding moiety is fused to the Fc domain through an immunoglobulin hinge region. In a specific embodiment, the immunoglobulin hinge region is a human IgG₁ hinge region.

In one embodiment the first antigen binding moiety comprises an antigen binding domain of an antibody, comprising an antibody heavy chain variable region and an antibody light chain variable region. In a particular embodiment the first antigen binding moiety is a Fab molecule. In one embodiment the Fab molecule is fused at its heavy or light chain carboxy-terminus to the amino-terminal amino acid of one of the two subunits of the Fc domain. In a particular embodiment the Fab molecule is fused at its heavy chain carboxy-terminus to the amino-terminal amino acid of one of the two subunits of the Fc domain. In a more particular embodiment the Fab molecule is fused to the Fc domain through an immunoglobulin hinge region. In a specific embodiment, the immunoglobulin hinge region is a human IgG₁ hinge region.

In one embodiment the immunoconjugate essentially consists of an antigen binding moiety, an Fc domain consisting of two subunits, an effector moiety, and optionally one or more linker peptides, wherein said antigen binding domain is a Fab molecule and is fused at its heavy chain carboxy-terminus to the amino-terminal amino acid of one of the two subunits of the Fc domain, and wherein said effector moiety is fused either (i) to the amino-terminal amino acid of the other one of the two subunits of the Fc domain, or (ii) to the carboxy-terminal amino acid of one of the two subunits of the Fc domain. In the latter case, the effector moiety and the first antigen binding moiety may both be fused to the same subunit of the Fc domain, or may each be fused to a different one of the two subunits of the Fc domain.

An immunoconjugate format with a single antigen binding moiety (for example as shown in FIGS. 2B and 2C) is useful, particularly in cases where internalization of the target antigen is to be expected following binding of a high affinity antigen binding moiety. In such cases, the presence of more than one antigen binding moiety per immunoconjugate may enhance internalization, thereby reducing availability of the target antigen.

In many other cases, however, it will be advantageous to have an immunoconjugate comprising two or more antigen binding moieties and a single effector moiety to optimize targeting to the target antigen versus the effector moiety receptor, and the pharmaceutical window of the immunoconjugate.

Thus, in a particular embodiment the immunoconjugate of the invention comprises a first and a second antigen binding moiety. In one embodiment each of said first and second antigen binding moieties is fused to the amino-terminal amino acid of one of the two subunits of the Fc domain.

The first and second antigen binding moieties may be fused to the Fc domain directly or through a linker peptide. In a particular embodiment each of said first and second antigen binding moieties is fused to a subunit of the Fc domain through an immunoglobulin hinge region. In a specific embodiment, the immunoglobulin hinge region is a human IgG₁ hinge region.

In one embodiment each of said first and second antigen binding moieties comprises an antigen binding domain of an antibody, comprising an antibody heavy chain variable region and an antibody light chain variable region. In a particular embodiment each of said first and second antigen binding moieties is a Fab molecule. In one embodiment each of said Fab molecules is fused at its heavy or light chain carboxy-terminus to the amino-terminal amino acid of one of the two subunits of the Fc domain. In a particular embodiment each of said Fab molecules is fused at its heavy chain carboxy-terminus to the amino-terminal amino acid of one of the two subunits of the Fc domain. In a more particular embodiment each of said Fab molecules is fused to a subunit of the Fc domain through an immunoglobulin hinge region. In a specific embodiment, the immunoglobulin hinge region is a human IgG₁ hinge region.

In one embodiment the first and the second antigen binding moiety and the Fc domain are part of an immunoglobulin molecule. In a particular embodiment the immunoglobulin molecule is an IgG class immunoglobulin. In an even more particular embodiment the immunoglobulin is an IgG₁ subclass immunoglobulin. In another particular embodiment the immunoglobulin is a human immunoglobulin. In other embodiments the immunoglobulin is a chimeric immunoglobulin or a humanized immunoglobulin. In one embodiment the effector moiety is fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains. The effector moiety may be fused to the immunoglobulin heavy chain directly or through a linker peptide. In a particular embodiment the immunoconjugate essentially consists of an immunoglobulin molecule, an effector moiety fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, and optionally one or more linker peptides.

In one embodiment the immunoconjugate comprises a polypeptide wherein a Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit and a polypeptide wherein an Fc domain subunit shares a carboxy-terminal peptide bond with an effector moiety polypeptide.

In another embodiment, the immunoconjugate comprises a polypeptide wherein a first Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit, and a polypeptide wherein a second Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit, which in turn shares a carboxy-terminal peptide bond with an effector moiety polypeptide. In a further embodiment the immunoconjugate comprises a polypeptide wherein a Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit and a polypeptide wherein an effector moiety polypeptide shares a carboxy-terminal peptide bond with an Fc domain subunit. In some embodiments the immunoconjugate further comprises a Fab light chain polypeptide. In certain embodiments the polypeptides are covalently linked, e.g., by a disulfide bond.

According to any of the above embodiments, components of the immunoconjugate (e.g. effector moiety, antigen binding moiety, Fc domain) may be linked directly or through various linkers, particularly peptide linkers comprising one or more amino acids, typically about 2-20 amino acids, that are described herein or are known in the art. Suitable, non-immunogenic linker peptides include, for example, (G4S)_(n), (SG₄)_(n) or G₄(SG₄)_(n) linker peptides, wherein n is generally a number between 1 and 10, typically between 2 and 4.

Fc Domain

The Fc domain of the immunoconjugate consists of a pair of polypeptide chains comprising heavy chain domains of an immunoglobulin molecule. For example, the Fc domain of an immunoglobulin G (IgG) molecule is a dimer, each subunit of which comprises the CH2 and CH3 IgG heavy chain constant domains. The two subunits of the Fc domain are capable of stable association with each other. In one embodiment the immunoconjugate of the invention comprises not more than one Fc domain.

In one embodiment according the invention the Fc domain of the immunoconjugate is an IgG Fc domain. In a particular embodiment the Fc domain is an IgG₁ Fc domain. In another embodiment, the Fc domain is an IgG₄ Fc domain. In a further particular embodiment the Fc domain is human. An exemplary sequence of a human IgG₁ Fc region is given in SEQ ID NO: 1.

The Fc domain confers to the immunoconjugate a greatly prolonged serum-half life as compared to immunoconjugate formats lacking an Fc domain. Particularly when the immunoconjugate comprises an effector moiety of rather weak activity (but e.g. reduced toxicity), a long half-life might be essential to achieve optimal efficacy in vivo. Moreover, the Fc domain can mediate effector functions, as will be further discussed below.

Fc Domain Modifications Promoting Heterodimerization

Immunoconjugates according to the invention comprise only one single effector moiety, fused to one of the two subunits of the Fc domain, thus they comprise two non-identical polypeptide chains. Recombinant co-expression of these polypeptides and subsequent dimerization leads to several possible combinations of the two polypeptides, out of which only heterodimers of the two non-identical polypeptides are useful according to the invention. To improve the yield and purity of immunoconjugates in recombinant production, it can thus be advantageous to introduce in the Fc domain of the immunoconjugate a modification which hinders the formation of homodimers of two identical polypeptides (i.e. two polypeptides comprising an effector moiety, or two polypeptides lacking an effector moiety) and/or promotes the formation of heterodimers of a polypeptide comprising an effector moiety and a polypeptide lacking an effector moiety.

Accordingly, in certain embodiments according to the invention the Fc domain of the immunoconjugate comprises a modification promoting heterodimerization of two non-identical polypeptide chains. The site of most extensive protein-protein interaction between the two polypeptide chains of a human IgG Fc domain is in the CH3 domain of the Fc domain. Thus, in one embodiment said modification is in the CH3 domain of the Fc domain.

In a specific embodiment said modification is a knob-into-hole modification, comprising a knob modification in one of the two subunits of the Fc domain and a hole modification in the other one of the two subunits of the Fc domain.

The knob-into-hole technology is described e.g. in U.S. Pat. No. 5,731,168; 7,695,936; Ridgway et al., Prot Eng 9, 617-621 (1996) and Carter, J Immunol Meth 248, 7-15 (2001). Generally, the method involves introducing a protuberance (“knob”) at the interface of a first polypeptide and a corresponding cavity (“hole”) in the interface of a second polypeptide, such that the protuberance can be positioned in the cavity so as to promote heterodimer formation and hinder homodimer formation. Protuberances are constructed by replacing small amino acid side chains from the interface of the first polypeptide with larger side chains (e.g. tyrosine or tryptophan). Compensatory cavities of identical or similar size to the protuberances are created in the interface of the second polypeptide by replacing large amino acid side chains with smaller ones (e.g. alanine or threonine). The protuberance and cavity can be made by altering the nucleic acid encoding the polypeptides, e.g. by site-specific mutagenesis, or by peptide synthesis. In a specific embodiment a knob modification comprises the amino acid substitution T366W in one of the two subunits of the Fc domain, and the hole modification comprises the amino acid substitutions T366S, L368A and Y407V in the other one of the two subunits of the Fc domain. In a further specific embodiment, the subunit of the Fc domain comprising the knob modification additionally comprises the amino acid substitution S354C, and the subunit of the Fc domain comprising the hole modification additionally comprises the amino acid substitution Y349C. Introduction of these two cysteine residues results in formation of a disulfide bridge between the two subunits of the Fc region, further stabilizing the dimer (Carter, J Immunol Methods 248, 7-15 (2001)).

In an alternative embodiment a modification promoting heterodimerization of two non-identical polypeptide chains comprises a modification mediating electrostatic steering effects, e.g. as described in PCT publication WO 2009/089004. Generally, this method involves replacement of one or more amino acid residues at the interface of the two polypeptide chains by charged amino acid residues so that homodimer formation becomes electrostatically unfavorable but heterodimerization electrostatically favorable.

In a particular embodiment the effector moiety is fused to the amino- or carboxy-terminal amino acid of the subunit of the Fc domain comprising the knob modification. Without wishing to be bound by theory, fusion of the effector moiety to the knob-containing subunit of the Fc domain will further minimize the generation of homodimeric immunoconjugates comprising two effector moieties (steric clash of two knob-containing polypeptides).

Fc Domain Modifications Altering Fc Receptor Binding

In certain embodiments of the invention the Fc domain of the immunoconjugate is engineered to have altered binding affinity to an Fc receptor, specifically altered binding affinity to an Fcγ receptor, as compared to a non-engineered Fc domain.

Binding to Fc receptors can be easily determined e.g. by ELISA, or by Surface Plasmon Resonance (SPR) using standard instrumentation such as a BIAcore instrument (GE Healthcare), and Fc receptors such as may be obtained by recombinant expression. A suitable such binding assay is described herein. Alternatively, binding affinity of Fc domains or immunoconjugates comprising an Fc domain for Fc receptors may be evaluated using cell lines known to express particular Fc receptors, such as NK cells expressing FcγIIIa receptor.

In some embodiments the Fc domain of the immunoconjugate is engineered to have altered effector functions, particularly altered ADCC, as compared to a non-engineered Fc domain.

Effector function of an Fc domain, or an immunoconjugate comprising an Fc domain, can be measured by methods known in the art. A suitable assay for measuring ADCC is described herein. Other examples of in vitro assays to assess ADCC activity of a molecule of interest are described in U.S. Pat. No. 5,500,362; Hellstrom et al. Proc Natl Acad Sci USA 83, 7059-7063 (1986) and Hellstrom et al., Proc Natl Acad Sci USA 82, 1499-1502 (1985); U.S. Pat. No. 5,821,337; Bruggemann et al., J Exp Med 166, 1351-1361 (1987). Alternatively, non-radioactive assays methods may be employed (see, for example, ACTI™ non-radioactive cytotoxicity assay for flow cytometry (CellTechnology, Inc. Mountain View, Calif.); and CytoTox 96® non-radioactive cytotoxicity assay (Promega, Madison, Wis.)). Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, or additionally, ADCC activity of the molecule of interest may be assessed in vivo, e.g. in a animal model such as that disclosed in Clynes et al., Proc Natl Acad Sci USA 95, 652-656 (1998).

In some embodiments binding of the Fc domain to a complement component, specifically to C1q, is altered. Accordingly, in some embodiments wherein the Fc domain is engineered to have altered effector function, said altered effector function includes altered CDC. C1q binding assays may be carried out to determine whether the immunoconjugate is able to bind C1q and hence has CDC activity. See e.g., C1q and C3c binding ELISA in WO 2006/029879 and WO 2005/100402. To assess complement activation, a CDC assay may be performed (see, for example, Gazzano-Santoro et al., J Immunol Methods 202, 163 (1996); Cragg et al., Blood 101, 1045-1052 (2003); and Cragg and Glennie, Blood 103, 2738-2743 (2004)).

a) Decreased Fc Receptor Binding and/or Effector Function

The Fc domain confers to the immunoconjugate favorable pharmacokinetic properties, including a long serum half-life which contributes to good accumulation in the target tissue and a favorable tissue-blood distribution ratio. At the same time it may, however, lead to undesirable targeting of the immunoconjugate to cells expressing Fc receptors rather than to the preferred antigen-bearing cells. Moreover, the co-activation of Fc receptor signaling pathways may lead to cytokine release which, in combination with the effector moiety and the long half-life of the immunoconjugate, results in excessive activation of cytokine receptors and severe side effects upon systemic administration. In line with this, conventional IgG-IL-2 immunoconjugates have been described to be associated with infusion reactions (see e.g. King et al., J Clin Oncol 22, 4463-4473 (2004)).

Accordingly, in particular embodiments according to the invention the Fc domain of the immunoconjugate is engineered to have reduced binding affinity to an Fc receptor. In one such embodiment the Fc domain comprises one or more amino acid mutation that reduces the binding affinity of the Fc domain to an Fc receptor. Typically, the same one or more amino acid mutation is present in each of the two subunits of the Fc domain. In one embodiment said amino acid mutation reduces the binding affinity of the Fc domain to the Fc receptor by at least 2-fold, at least 5-fold, or at least 10-fold. In embodiments where there is more than one amino acid mutation that reduces the binding affinity of the Fc domain to the Fc receptor, the combination of these amino acid mutations may reduce the binding affinity of the Fc domain to the Fc receptor by at least 10-fold, at least 20-fold, or even at least 50-fold. In one embodiment the immunoconjugate comprising an engineered Fc domain exhibits less than 20%, particularly less than 10%, more particularly less than 5% of the binding affinity to an Fc receptor as compared to an immunoconjugate comprising a non-engineered Fc domain. In one embodiment the Fc receptor is an activating Fc receptor. In a specific embodiment the Fc receptor is an Fcγ receptor, more specifically an FcγRIIIa, FcγRI or FcγRIIa receptor. Preferably, binding to each of these receptors is reduced. In some embodiments binding affinity to a complement component, specifically binding affinity to C1q, is also reduced. In one embodiment binding affinity to neonatal Fc receptor (FcRn) is not reduced. Substantially similar binding to FcRn, i.e. preservation of the binding affinity of the Fc domain to said receptor, is achieved when the Fc domain (or the immunoconjugate comprising said Fc domain) exhibits greater than about 70% of the binding affinity of a non-engineered form of the Fc domain (or the immunoconjugate comprising said non-engineered form of the Fc domain) to FcRn. Fc domains, or immunoconjugates of the invention comprising said Fc domains, may exhibit greater than about 80% and even greater than about 90% of such affinity. In one embodiment the amino acid mutation is an amino acid substitution. In one embodiment the Fc domain comprises an amino acid substitution at position P329. In a more specific embodiment the amino acid substitution is P329A or P329G, particularly P329G. In one embodiment the Fc domain comprises a further amino acid substitution at a position selected from 5228, E233, L234, L235, N297 and P331. In a more specific embodiment the further amino acid substitution is S228P, E233P, L234A, L235A, L235E, N297A, N297D or P331 S. In a particular embodiment the Fc domain comprises amino acid substitutions at positions P329, L234 and L235. In a more particular embodiment the Fc domain comprises the amino acid mutations L234A, L235A and P329G (LALA P329G). This combination of amino acid substitutions almost completely abolishes Fcγ receptor binding of a human IgG Fc domain, as described in European patent application no. EP 11160251.2, incorporated herein by reference in its entirety. EP 11160251.2 also describes methods of preparing such mutant Fc domains and methods for determining its properties such as Fc receptor binding or effector functions.

Mutant Fc domains can be prepared by amino acid deletion, substitution, insertion or modification using genetic or chemical methods well known in the art. Genetic methods may include site-specific mutagenesis of the encoding DNA sequence, PCR, gene synthesis, and the like. The correct nucleotide changes can be verified for example by sequencing.

In one embodiment the Fc domain is engineered to have decreased effector function, compared to a non-engineered Fc domain. The decreased effector function can include, but is not limited to, one or more of the following: decreased complement dependent cytotoxicity (CDC), decreased antibody-dependent cell-mediated cytotoxicity (ADCC), decreased antibody-dependent cellular phagocytosis (ADCP), decreased cytokine secretion, decreased immune complex-mediated antigen uptake by antigen-presenting cells, decreased binding to NK cells, decreased binding to macrophages, decreased binding to monocytes, decreased binding to polymorphonuclear cells, decreased direct signaling inducing apoptosis, decreased crosslinking of target-bound antibodies, decreased dendritic cell maturation, or decreased T cell priming.

In one embodiment the decreased effector function is one or more selected from the group of decreased CDC, decreased ADCC, decreased ADCP, and decreased cytokine secretion. In a particular embodiment the decreased effector function is decreased ADCC. In one embodiment the decreased ADCC is less than 20% of the ADCC induced by a non-engineered Fc domain (or an immunoconjugate comprising a non-engineered Fc domain).

In addition to the Fc domains described hereinabove and in European patent application no. EP 11160251.2, Fc domains with reduced Fc receptor binding and/or effector function also include those with substitution of one or more of Fc domain residues 238, 265, 269, 270, 297, 327 and 329 (U.S. Pat. No. 6,737,056). Such Fc mutants include Fc mutants with substitutions at two or more of amino acid positions 265, 269, 270, 297 and 327, including the so-called “DANA” Fc mutant with substitution of residues 265 and 297 to alanine (U.S. Pat. No. 7,332,581).

IgG₄ antibodies exhibit reduced binding affinity to Fc receptors and reduced effector functions as compared to IgG₁ antibodies. Hence, in some embodiments the Fc domain of the T cell activating bispecific antigen binding molecules of the invention is an IgG₄ Fc domain, particularly a human IgG₄ Fc domain. In one embodiment the IgG₄ Fc domain comprises amino acid substitutions at position S228, specifically the amino acid substitution S228P. To further reduce its binding affinity to an Fc receptor and/or its effector function, in one embodiment the IgG₄ Fc domain comprises an amino acid substitution at position L235, specifically the amino acid substitution L235E. In another embodiment, the IgG₄ Fc domain comprises an amino acid substitution at position P329, specifically the amino acid substitution P329G. In a particular embodiment, the IgG₄ Fc domain comprises amino acid substitutions at positions S228, L235 and P329, specifically amino acid substitutions S228P, L235E and P329G. Such IgG₄ Fc domain mutants and their Fcγ receptor binding properties are described in European patent application no. EP 11160251.2, incorporated herein by reference in its entirety.

b) Increased Fc Receptor Binding and/or Effector Function

Conversely, there may be situations where it is desirable to maintain or even enhance Fc receptor binding and/or effector functions of immunoconjugates, for example when the immunoconjugate is targeted to a highly specific tumor antigen. Hence, in certain embodiments the Fc domain of the immunoconjugates of the invention is engineered to have increased binding affinity to an Fc receptor. Increased binding affinity may be an increase in the binding affinity of the Fc domain to the Fc receptor by at least 2-fold, at least 5-fold, or at least 10-fold. In one embodiment the Fc receptor is an activating Fc receptor. In a specific embodiment the Fc receptor is an Fcγ receptor. In one embodiment the Fc receptor is selected from the group of FcγRIIIa, FcγRI and FcγRIIa. In a particular embodiment the Fc receptor is FcγRIIIa.

In one such embodiment the Fc domain is engineered to have an altered oligosaccharide structure compared to a non-engineered Fc domain. In a particular such embodiment the Fc domain comprises an increased proportion of non-fucosylated oligosaccharides, compared to a non-engineered Fc domain. In a more specific embodiment, at least about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%, particularly at least about 50%, more particularly at least about 70%, of the N-linked oligosaccharides in the Fc domain of the immunoconjugate are non-fucosylated. The non-fucosylated oligosaccharides may be of the hybrid or complex type. In another specific embodiment the Fc domain comprises an increased proportion of bisected oligosaccharides, compared to a non-engineered Fc domain. In a more specific embodiment, at least about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%, particularly at least about 50%, more particularly at least about 70%, of the N-linked oligosaccharides in the Fc domain of the immunoconjugate are bisected. The bisected oligosaccharides may be of the hybrid or complex type. In yet another specific embodiment the Fc domain comprises an increased proportion of bisected, non-fucosylated oligosaccharides, compared to a non-engineered Fc domain. In a more specific embodiment, at least about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%, particularly at least about 15%, more particularly at least about 25%, at least about 35% or at least about 50%, of the N-linked oligosaccharides in the Fc domain of the immunoconjugate are bisected, non-fucosylated. The bisected, non-fucosylated oligosaccharides may be of the hybrid or complex type.

The oligosaccharide structures in the immunoconjugate Fc domain can be analysed by methods well known in the art, e.g. by MALDI TOF mass spectrometry as described in Umana et al., Nat Biotechnol 17, 176-180 (1999) or Ferrara et al., Biotechn Bioeng 93, 851-861 (2006). The percentage of non-fucosylated oligosaccharides is the amount of oligosaccharides lacking fucose residues, relative to all oligosaccharides attached to Asn 297 (e.g. complex, hybrid and high mannose structures) and identified in an N-glycosidase F treated sample by MALDI TOF MS. Asn 297 refers to the asparagine residue located at about position 297 in the Fc domain (EU numbering of Fc region residues); however, Asn297 may also be located about ±3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300, due to minor sequence variations in immunoglobulins. The percentage of bisected, or bisected non-fucosylated, oligosaccharides is determined analogously.

Modification of the glycosylation in the Fc domain of the immunoconjugate may result from production of the immunoconjugate in a host cell that has been manipulated to express altered levels of one or more polypeptides having glycosyltransferase activity.

In one embodiment the Fc domain of the immunoconjugate is engineered to have an altered oligosaccharide structure, as compared to a non-engineered Fc domain, by producing the immunoconjugate in a host cell having altered activity of one or more glycosyltransferase. Glycosyltransferases include for example β(1,4)-N-acetylglucosaminyltransferase III (GnTIII), β(1,4)-galactosyltransferase (GalT), β(1,2)-N-acetylglucosaminyltransferase I (GnTI), β(1,2)-N-acetylglucosaminyltransferase II (GnTII) and α(1,6)-fucosyltransferase. In a specific embodiment the Fc domain of the immunoconjugate is engineered to comprise an increased proportion of non-fucosylated oligosaccharides, as compared to a non-engineered Fc domain, by producing the immunoconjugate in a host cell having increased β(1,4)-N-acetylglucosaminyltransferase III (GnTIII) activity. In an even more specific embodiment the host cell additionally has increased α-mannosidase II (ManII) activity. The glycoengineering methodology that can be used for glycoengineering immunoconjugates of the present invention has been described in greater detail in Umana et al., Nat Biotechnol 17, 176-180 (1999); Ferrara et al., Biotechn Bioeng 93, 851-861 (2006); WO 99/54342 (U.S. Pat. No. 6,602,684; EP 1071700); WO 2004/065540 (U.S. Pat. Appl. Publ. No. 2004/0241817; EP 1587921), WO 03/011878 (U.S. Pat. Appl. Publ. No. 2003/0175884), the content of each of which is expressly incorporated herein by reference in its entirety.

Generally, any type of cultured cell line, including the cell lines discussed herein, can be used to generate cell lines for the production of immunoconjugates with altered glycosylation pattern. Particular cell lines include CHO cells, BHK cells, NS0 cells, SP2/0 cells, YO myeloma cells, P3X63 mouse myeloma cells, PER cells, PER.C6 cells or hybridoma cells, and other mammalian cells. In certain embodiments, the host cells have been manipulated to express increased levels of one or more polypeptides having β(1,4)-N-acetylglucosaminyltransferase III (GnTIII) activity. In certain embodiments the host cells have been further manipulated to express increased levels of one or more polypeptides having α-mannosidase II (ManII) activity. In a specific embodiment, the polypeptide having GnTIII activity is a fusion polypeptide comprising the catalytic domain of GnTIII and the Golgi localization domain of a heterologous Golgi resident polypeptide. Particularly, said Golgi localization domain is the Golgi localization domain of mannosidase II. Methods for generating such fusion polypeptides and using them to produce antibodies with increased effector functions are disclosed in Ferrara et al., Biotechn Bioeng 93, 851-861 (2006) and WO 2004/065540, the entire contents of which are expressly incorporated herein by reference.

The host cells which contain a coding sequence of an immunoconjugate of the invention and/or a coding sequence of a polypeptide having glycosyltransferase activity, and which express the biologically active gene products, may be identified e.g. by DNA-DNA or DNA-RNA hybridization, the presence or absence of “marker” gene functions, assessing the level of transcription as measured by the expression of the respective mRNA transcripts in the host cell, or detection of the gene product as measured by immunoassay or by its biological activity—methods which are well known in the art. GnTIII or Man II activity can be detected e.g. by employing a lectin which binds to biosynthesis products of GnTIII or ManII, respectively. An example for such a lectin is the E₄-PHA lectin which binds preferentially to oligosaccharides containing bisecting GlcNAc. Biosynthesis products (i.e. specific oligosaccharide structures) of polypeptides having GnTIII or ManII activity can also be detected by mass spectrometric analysis of oligosaccharides released from glycoproteins produced by cells expressing said polypeptides. Alternatively, a functional assay which measures the increased effector function and/or increased Fc receptor binding, mediated by immunoconjugates produced by the cells engineered with the polypeptide having GnTIII or ManII activity may be used.

In another embodiment the Fc domain is engineered to comprise an increased proportion of non-fucosylated oligosaccharides, as compared to a non-engineered Fc domain, by producing the immunoconjugate in a host cell having decreased α(1,6)-fucosyltransferase activity. A host cell having decreased α(1,6)-fucosyltransferase activity may be a cell in which the α(1,6)-fucosyltransferase gene has been disrupted or otherwise deactivated, e.g. knocked out (see Yamane-Ohnuki et al., Biotech Bioeng 87, 614 (2004); Kanda et al., Biotechnol Bioeng 94(4), 680-688 (2006); Niwa et al., J Immunol Methods 306, 151-160 (2006)).

Other examples of cell lines capable of producing defucosylated immunoconjugates include Lec13 CHO cells deficient in protein fucosylation (Ripka et al., Arch Biochem Biophys 249, 533-545 (1986); US Pat. Appl. No. US 2003/0157108; and WO 2004/056312, especially at Example 11). The immunoconjugates of the present invention can alternatively be glycoengineered to have reduced fucose residues in the Fc domain according to the techniques disclosed in EP 1 176 195 A1, WO 03/084570, WO 03/085119 and U.S. Pat. Appl. Pub. Nos. 2003/0115614, 2004/093621, 2004/110282, 2004/110704, 2004/132140, U.S. Pat. No. 6,946,292 (Kyowa), e.g. by reducing or abolishing the activity of a GDP-fucose transporter protein in the host cells used for immunoconjugate production.

Glycoengineered immunoconjugates of the invention may also be produced in expression systems that produce modified glycoproteins, such as those taught in WO 2003/056914 (GlycoFi, Inc.) or in WO 2004/057002 and WO 2004/024927 (Greenovation).

In one embodiment the Fc domain of the immunoconjugate is engineered to have increased effector function, compared to a non-engineered Fc domain. The increased effector function can include, but is not limited to, one or more of the following: increased complement dependent cytotoxicity (CDC), increased antibody-dependent cell-mediated cytotoxicity (ADCC), increased antibody-dependent cellular phagocytosis (ADCP), increased cytokine secretion, increased immune complex-mediated antigen uptake by antigen-presenting cells, increased binding to NK cells, increased binding to macrophages, increased binding to monocytes, increased binding to polymorphonuclear cells, increased direct signaling inducing apoptosis, increased crosslinking of target-bound antibodies, increased dendritic cell maturation, or increased T cell priming.

In one embodiment the increased effector function is one or more selected from the group of increased CDC, increased ADCC, increased ADCP, and increased cytokine secretion. In a particular embodiment the increased effector function is increased ADCC. In one embodiment ADCC induced by an engineered Fc domain (or an immunoconjugate comprising an engineered Fc domain) is a least 2-fold increased as compared to ADCC induced by a non-engineered Fc domain (or an immunoconjugate comprising a non-engineered Fc domain).

Effector Moieties

The effector moieties for use in the invention are generally polypeptides that influence cellular activity, for example, through signal transduction pathways. Accordingly, the effector moiety of the immunoconjugate useful in the invention can be associated with receptor-mediated signaling that transmits a signal from outside the cell membrane to modulate a response within the cell. For example, an effector moiety of the immunoconjugate can be a cytokine. In particular embodiments the effector moiety is human.

In certain embodiments the effector moiety is a single chain effector moiety. In a particular embodiment the effector moiety is a cytokine. Examples of useful cytokines include, but are not limited to, GM-CSF, IL-la, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-21, IFN-α, IFN-β, IFN-γ, MIP-1α, MIP-1β, TGF-β, TNF-α, and TNF-β. In one embodiment the effector moiety of the immunoconjugate is a cytokine selected from the group of GM-CSF, IL-2, IL-7, IL-8, IL-10, IL-12, IL-15, IL-21, IFN-α, IFN-γ, MIP-1α, MIP-1β and TGF-β. In one embodiment the effector moiety of the immunoconjugate is a cytokine selected from the group of IL-2, IL-7, IL-10, IL-12, IL-15, IFN-α, and IFN-γ. In certain embodiments the cytokine effector moiety is mutated to remove N- and/or O-glycosylation sites. Elimination of glycosylation increases homogeneity of the product obtainable in recombinant production.

In a particular embodiment the effector moiety of the immunoconjugate is IL-2. In a specific embodiment, the IL-2 effector moiety can elicit one or more of the cellular responses selected from the group consisting of: proliferation in an activated T lymphocyte cell, differentiation in an activated T lymphocyte cell, cytotoxic T cell (CTL) activity, proliferation in an activated B cell, differentiation in an activated B cell, proliferation in a natural killer (NK) cell, differentiation in a NK cell, cytokine secretion by an activated T cell or an NK cell, and NK/lymphocyte activated killer (LAK) antitumor cytotoxicity. In another particular embodiment the IL-2 effector moiety is a mutant IL-2 effector moiety having reduced binding affinity to the α-subunit of the IL-2 receptor. Together with the β- and γ-subunits (also known as CD122 and CD132, respectively), the α-subunit (also known as CD25) forms the heterotrimeric high-affinity IL-2 receptor, while the dimeric receptor consisting only of the β- and γ-subunits is termed the intermediate-affinity IL-2 receptor. As described in PCT patent application number PCT/EP2012/051991, which is incorporated herein by reference in its entirety, a mutant IL-2 polypeptide with reduced binding to the α-subunit of the IL-2 receptor has a reduced ability to induce IL-2 signaling in regulatory T cells, induces less activation-induced cell death (AICD) in T cells, and has a reduced toxicity profile in vivo, compared to a wild-type IL-2 polypeptide. The use of such an effector moiety with reduced toxicity is particularly advantageous in an immunoconjugate according to the invention, having a long serum half-life due to the presence of an Fc domain. In one embodiment, the mutant IL-2 effector moiety of the immunoconjugate according to the invention comprises at least one amino acid mutation that reduces or abolishes the affinity of the mutant IL-2 effector moiety to the α-subunit of the IL-2 receptor (CD25) but preserves the affinity of the mutant IL-2 effector moiety to the intermediate-affinity IL-2 receptor (consisting of the β- and γ-subunits of the IL-2 receptor), compared to the non-mutated IL-2 effector moiety. In one embodiment the one or more amino acid mutations are amino acid substitutions. In a specific embodiment, the mutant IL-2 effector moiety comprises one, two or three amino acid substitutions at one, two or three position(s) selected from the positions corresponding to residue 42, 45, and 72 of human IL-2. In a more specific embodiment, the mutant IL-2 effector moiety comprises three amino acid substitutions at the positions corresponding to residue 42, 45 and 72 of human IL-2. In an even more specific embodiment, the mutant IL-2 effector moiety is human IL-2 comprising the amino acid substitutions F42A, Y45A and L72G. In one embodiment the mutant IL-2 effector moiety additionally comprises an amino acid mutation at a position corresponding to position 3 of human IL-2, which eliminates the O-glycosylation site of IL-2. Particularly, said additional amino acid mutation is an amino acid substitution replacing a threonine residue by an alanine residue. A particular mutant IL-2 effector moiety useful in the invention comprises four amino acid substitutions at positions corresponding to residues 3, 42, 45 and 72 of human IL-2. Specific amino acid substitutions are T3A, F42A, Y45A and L72G. As demonstrated in PCT patent application number PCT/EP2012/051991 and in the appended Examples, said quadruple mutant IL-2 polypeptide (IL-2 qm) exhibits no detectable binding to CD25, reduced ability to induce apoptosis in T cells, reduced ability to induce IL-2 signaling in T_(reg) cells, and a reduced toxicity profile in vivo. However, it retains ability to activate IL-2 signaling in effector cells, to induce proliferation of effector cells, and to generate IFN-γ as a secondary cytokine by NK cells.

The IL-2 or mutant IL-2 effector moiety according to any of the above embodiments may comprise additional mutations that provide further advantages such as increased expression or stability. For example, the cysteine at position 125 may be replaced with a neutral amino acid such as alanine, to avoid the formation of disulfide-bridged IL-2 dimers. Thus, in certain embodiments the IL-2 or mutant IL-2 effector moiety of the immunoconjugate according to the invention comprises an additional amino acid mutation at a position corresponding to residue 125 of human IL-2. In one embodiment said additional amino acid mutation is the amino acid substitution C125A.

In a specific embodiment the IL-2 effector moiety of the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 2. In another specific embodiment the IL-2 effector moiety of the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 3.

In another embodiment the effector moiety of the immunoconjugate is IL-12. In a specific embodiment said IL-12 effector moiety is a single chain IL-12 effector moiety. In an even more specific embodiment the single chain IL-12 effector moiety comprises the polypeptide sequence of SEQ ID NO: 4. In one embodiment, the IL-12 effector moiety can elicit one or more of the cellular responses selected from the group consisting of: proliferation in a NK cell, differentiation in a NK cell, proliferation in a T cell, and differentiation in a T cell.

In another embodiment the effector moiety of the immunoconjugate is IL-10. In a specific embodiment said IL-10 effector moiety is a single chain IL-10 effector moiety. In an even more specific embodiment the single chain IL-10 effector moiety comprises the polypeptide sequence of SEQ ID NO: 5. In another specific embodiment the IL-10 effector moiety is a monomeric IL-10 effector moiety. In a more specific embodiment the monomeric IL-10 effector moiety comprises the polypeptide sequence of SEQ ID NO: 6. In one embodiment, the IL-10 effector moiety can elicit one or more of the cellular responses selected from the group consisting of: inhibition of cytokine secretion, inhibition of antigen presentation by antigen presenting cells, reduction of oxygen radical release, and inhibition of T cell proliferation. An immunoconjugate according to the invention wherein the effector moiety is IL-10 is particularly useful for downregulation of inflammation, e.g. in the treatment of an inflammatory disorder.

In another embodiment the effector moiety of the immunoconjugate is IL-15. In a specific embodiment said IL-15 effector moiety is a mutant IL-15 effector moiety having reduced binding affinity to the α-subunit of the IL-15 receptor. Without wishing to be bound by theory, a mutant IL-15 polypeptide with reduced binding to to the α-subunit of the IL-15 receptor has a reduced ability to bind to fibroblasts throughout the body, resulting in improved pharmacokinetics and toxicity profile, compared to a wild-type IL-15 polypeptide. The use of an effector moiety with reduced toxicity, such as the described mutant IL-2 and mutant IL-15 effector moieties, is particularly advantageous in an immunoconjugate according to the invention, having a long serum half-life due to the presence of an Fc domain. In one embodiment the mutant IL-15 effector moiety of the immunoconjugate according to the invention comprises at least one amino acid mutation that reduces or abolishes the affinity of the mutant IL-15 effector moiety to the α-subunit of the IL-15 receptor but preserves the affinity of the mutant IL-15 effector moiety to the intermediate-affinity IL-15/IL-2 receptor (consisting of the β- and γ-subunits of the IL-15/IL-2 receptor), compared to the non-mutated IL-15 effector moiety. In one embodiment the amino acid mutation is an amino acid substitution. In a specific embodiment, the mutant IL-15 effector moiety comprises an amino acid substitution at the position corresponding to residue 53 of human IL-15. In a more specific embodiment, the mutant IL-15 effector moiety is human IL-15 comprising the amino acid substitution E53A. In one embodiment the mutant IL-15 effector moiety additionally comprises an amino acid mutation at a position corresponding to position 79 of human IL-15, which eliminates the N-glycosylation site of IL-15. Particularly, said additional amino acid mutation is an amino acid substitution replacing an asparagine residue by an alanine residue. In an even more specific embodiment the IL-15 effector moiety comprises the polypeptide sequence of SEQ ID NO: 7. In one embodiment, the IL-15 effector moiety can elicit one or more of the cellular responses selected from the group consisting of: proliferation in an activated T lymphocyte cell, differentiation in an activated T lymphocyte cell, cytotoxic T cell (CTL) activity, proliferation in an activated B cell, differentiation in an activated B cell, proliferation in a natural killer (NK) cell, differentiation in a NK cell, cytokine secretion by an activated T cell or an NK cell, and NK/lymphocyte activated killer (LAK) antitumor cytotoxicity.

Mutant cytokine molecules useful as effector moieties in the immunoconjugates can be prepared by deletion, substitution, insertion or modification using genetic or chemical methods well known in the art. Genetic methods may include site-specific mutagenesis of the encoding DNA sequence, PCR, gene synthesis, and the like. The correct nucleotide changes can be verified for example by sequencing. Substitution or insertion may involve natural as well as non-natural amino acid residues. Amino acid modification includes well known methods of chemical modification such as the addition or removal of glycosylation sites or carbohydrate attachments, and the like.

In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is GM-CSF. In a specific embodiment, the GM-CSF effector moiety can elicit proliferation and/or differentiation in a granulocyte, a monocyte or a dendritic cell. In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is IFN-α. In a specific embodiment, the IFN-α effector moiety can elicit one or more of the cellular responses selected from the group consisting of: inhibiting viral replication in a virus-infected cell, and upregulating the expression of major histocompatibility complex I (MHC I). In another specific embodiment, the IFN-α effector moiety can inhibit proliferation in a tumor cell. In one embodiment the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is IFN-γ. In a specific embodiment, the IFN-γ effector moiety can elicit one or more of the cellular responses selected from the group of: increased macrophage activity, increased expression of MHC molecules, and increased NK cell activity. In one embodiment the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is IL-7. In a specific embodiment, the IL-7 effector moiety can elicit proliferation of T and/or B lymphocytes. In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is IL-8. In a specific embodiment, the IL-8 effector moiety can elicit chemotaxis in neutrophils. In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate, is MIP-1α. In a specific embodiment, the MIP-1α effector moiety can elicit chemotaxis in monocytes and T lymphocyte cells. In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is MIP-1β. In a specific embodiment, the MIP-1β effector moiety can elicit chemotaxis in monocytes and T lymphocyte cells. In one embodiment, the effector moiety, particularly a single-chain effector moiety, of the immunoconjugate is TGF-β. In a specific embodiment, the TGF-β effector moiety can elicit one or more of the cellular responses selected from the group consisting of: chemotaxis in monocytes, chemotaxis in macrophages, upregulation of IL-1 expression in activated macrophages, and upregulation of IgA expression in activated B cells.

In one embodiment, the immunoconjugate of the invention binds to an effector moiety receptor with a dissociation constant (K_(D)) that is at least about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10 times greater than that for a control effector moiety. In another embodiment, the immunoconjugate binds to an effector moiety receptor with a K_(D) that is at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 times greater than that for a corresponding immunoconjugate molecule comprising two or more effector moieties. In another embodiment, the immunoconjugate binds to an effector moiety receptor with a dissociation constant K_(D) that is about 10 times greater than that for a corresponding immunoconjugate molecule comprising two or more effector moieties.

Antigen Binding Moieties

The immunoconjugates of the invention comprise at least one antigen binding moiety. In particular embodiments, the immunoconjugates comprises two antigen binding moieties, i.e. a first and a second antigen binding moiety. In one embodiment the immunoconjugate comprises not more than two antigen binding moieties.

The antigen binding moiety of the immunoconjugate of the invention is generally a polypeptide molecule that binds to a specific antigenic determinant and is able to direct the entity to which it is attached (e.g. an effector moiety and an Fc domain) to a target site, for example to a specific type of tumor cell or tumor stroma that bears the antigenic determinant. The immunoconjugate can bind to antigenic determinants found, for example, on the surfaces of tumor cells, on the surfaces of virus-infected cells, on the surfaces of other diseased cells, free in blood serum, and/or in the extracellular matrix (ECM).

In certain embodiments the antigen binding moiety is directed to an antigen associated with a pathological condition, such as an antigen presented on a tumor cell or in a tumor cell environment, at a site of inflammation, or on a virus-infected cell.

Non-limiting examples of tumor antigens include MAGE, MART-1/Melan-A, gp100, Dipeptidyl peptidase IV (DPPIV), adenosine deaminase-binding protein (ADAbp), cyclophilin b, Colorectal associated antigen (CRC)-0017-1A/GA733, Carcinoembryonic Antigen (CEA) and its immunogenic epitopes CAP-1 and CAP-2, etv6, aml1, Prostate Specific Antigen (PSA) and its immunogenic epitopes PSA-1, PSA-2, and PSA-3, prostate-specific membrane antigen (PSMA), MAGE-family of tumor antigens (e.g., MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4, MAGE-A5, MAGE-A6, MAGE-A7, MAGE-A8, MAGE-A9, MAGE-A10, MAGE-A11, MAGE-A12, MAGE-Xp2 (MAGE-B2), MAGE-Xp3 (MAGE-B3), MAGE-Xp4 (MAGE-B4), MAGE-C1, MAGE-C2, MAGE-C3, MAGE-C4, MAGE-05), GAGE-family of tumor antigens (e.g., GAGE-1, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7, GAGE-8, GAGE-9), BAGE, RAGE, LAGE-1, NAG, GnT-V, MUM-1, CDK4, tyrosinase, p53, MUC family, HER2/neu, p21 ras, RCAS1, α-fetoprotein, E-cadherin, α-catenin, β-catenin and γ-catenin, p120ctn, gp100 Pmel117, PRAME, NY-ESO-1, cdc27, adenomatous polyposis coli protein (APC), fodrin, Connexin 37, Ig-idiotype, p15, gp75, GM2 and GD2 gangliosides, viral products such as human papilloma virus proteins, Smad family of tumor antigens, lmp-1, NA, EBV-encoded nuclear antigen (EBNA)-1, brain glycogen phosphorylase, SSX-1, SSX-2 (HOM-MEL-40), SSX-1, SSX-4, SSX-5, SCP-1 and CT-7, and c-erbB-2.

Non-limiting examples of viral antigens include influenza virus hemagglutinin, Epstein-Barr virus LMP-1, hepatitis C virus E2 glycoprotein, HIV gp160, and HIV gp120.

Non-limiting examples of ECM antigens include syndecan, heparanase, integrins, osteopontin, link, cadherins, laminin, laminin type EGF, lectin, fibronectin, notch, tenascin, and matrixin.

The immunoconjugates of the invention can bind to the following specific non-limiting examples of cell surface antigens: FAP, Her2, EGFR, IGF-1R, CD22 (B-cell receptor), CD23 (low affinity IgE receptor), CD30 (cytokine receptor), CD33 (myeloid cell surface antigen), CD40 (tumor necrosis factor receptor), IL-6R (IL6 receptor), CD20, MCSP, and PDGFβR (β platelet-derived growth factor receptor). In particular embodiments the antigen is a human antigen.

In certain embodiments the antigen-binding moiety is directed to an antigen presented on a tumor cell or in a tumor cell environment. In other embodiments the antigen binding moiety is directed to an antigen presented at a site of inflammation. In a specific embodiment the antigen-binding moiety is directed to an antigen selected from the group of Fibroblast Activation Protein (FAP), the A1 domain of Tenascin-C (TNC A1), the A2 domain of Tenascin-C (TNC A2), the Extra Domain B of Fibronectin (EDB), Carcinoembryonic Antigen (CEA), and Melanoma-associated Chondroitin Sulfate Proteoglycan (MCSP).

In one embodiment, the immunoconjugate of the invention comprises two or more antigen binding moieties, wherein each of these antigen binding moieties specifically binds to the same antigenic determinant.

The antigen binding moiety can be any type of antibody or fragment thereof that retains specific binding to an antigenic determinant. Antibody fragments include, but are not limited to, V_(H) fragments, V_(L) fragments, Fab fragments, F(ab)₂ fragments, scFv fragments, F_(V) fragments, minibodies, diabodies, triabodies, and tetrabodies (see e.g. Hudson and Souriau, Nature Med 9, 129-134 (2003)). In a particular embodiment the antigen binding moiety is a Fab molecule. In one embodiment said Fab molecule is human. In another embodiment said Fab molecule is humanized. In yet another embodiment said Fab molecule comprises human heavy and light chain constant regions.

In one embodiment the immunoconjugate comprises at least one, typically two or more antigen binding moieties that are specific for the Extra Domain B of fibronectin (EDB). In another embodiment the immunoconjugate comprises at least one, typically two or more antigen binding moieties that can compete with monoclonal antibody L19 for binding to an epitope of EDB. See, e.g., PCT publication WO 2007/128563 A1 (incorporated herein by reference in its entirety).

In yet another embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain derived from the L19 monoclonal antibody shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In a more specific embodiment the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 215 or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain derived from the L19 monoclonal antibody shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 213 or a variant thereof that retains functionality. In another embodiment the immunoconjugate comprises a Fab light chain derived from the L19 monoclonal antibody. In a more specific embodiment the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 217 or a variant thereof that retains functionality. In yet another embodiment the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 213, SEQ ID NO: 215 and SEQ ID NO: 217, or variants thereof that retain functionality. In another specific embodiment the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 216. In another specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 216. In another specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 214. In yet another specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 214. In another specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 218. In yet another specific embodiment the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 218.

In one embodiment the immunoconjugate of the invention comprises at least one, typically two or more antigen binding moieties that are specific for the A1 domain of Tenascin C (TNC-A1).

In another embodiment, the immunoconjugate comprises at least one, typically two or more antigen binding moieties that can compete with monoclonal antibody F16 for binding to an epitope of TNC-A1. See, e.g., PCT publication WO 2007/128563 A1 (incorporated herein by reference in its entirety). In one embodiment, the immunoconjugate comprises at least one, typically two or more antigen binding moieties that are specific for the A1 and/or the A4 domain of Tenascin C (TNC-A1 or TNC-A4 or TNC-A1/A4).

In a specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to either SEQ ID NO: 33 or SEQ ID NO: 35, or variants thereof that retain functionality. In another specific embodiment, the antigen binding moieties of the immunoconjugate comprise a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to either SEQ ID NO: 29 or SEQ ID NO: 31, or variants thereof that retain functionality. In a more specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to either SEQ ID NO: 33 or SEQ ID NO: 35 or variants thereof that retain functionality, and a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to either SEQ ID NO: 29 or SEQ ID NO: 31 or variants thereof that retain functionality. In another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to either SEQ ID NO: 34 or SEQ ID NO: 36. In yet another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by the polynucleotide sequence of either SEQ ID NO: 34 or SEQ ID NO: 36. In another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to either SEQ ID NO: 30 or SEQ ID NO: 32. In yet another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by the polynucleotide sequence of either SEQ ID NO: 30 or SEQ ID NO: 32.

In one embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A1 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In another embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A1 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment the immunoconjugate comprises both of these polypeptide sequences. In another embodiment, the immunoconjugate further comprises a Fab light chain specific for the A1 domain of Tenascin C. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In a particular embodiment, the immunoconjugate comprises at least one, typically two or more antigen binding moieties that are specific for the A2 domain of Tenascin C (TNC-A2). In a specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group of SEQ ID NO: 27, SEQ ID NO: 159, SEQ ID NO: 163, SEQ ID NO: 167, SEQ ID NO: 171, SEQ ID NO:175, SEQ ID NO: 179, SEQ ID NO: 183 and SEQ ID NO: 187, or variants thereof that retain functionality. In another specific embodiment, the antigen binding moieties of the immunoconjugate comprise a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group of SEQ ID NO: 23, SEQ ID NO: 25; SEQ ID NO: 157, SEQ ID NO: 161, SEQ ID NO:165, SEQ ID NO: 169, SEQ ID NO: 173, SEQ ID NO: 177, SEQ ID NO: 181 and SEQ ID NO: 185, or variants thereof that retain functionality. In a more specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group of SEQ ID NO: 27, SEQ ID NO: 159, SEQ ID NO: 163, SEQ ID NO: 167, SEQ ID NO: 171, SEQ ID NO:175, SEQ ID NO: 179, SEQ ID NO: 183 and SEQ ID NO: 187, or variants thereof that retain functionality, and a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group of SEQ ID NO: 23, SEQ ID NO: 25; SEQ ID NO: 157, SEQ ID NO: 161, SEQ ID NO:165, SEQ ID NO: 169, SEQ ID NO: 173, SEQ ID NO: 177, SEQ ID NO: 181 and SEQ ID NO: 185, or variants thereof that retain functionality. In a particular embodiment, the antigen binding moieties of the immunoconjugate comprise the heavy chain variable region sequence of SEQ ID NO: 27 and the light chain variable region sequence of SEQ ID NO: 25.

In another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group of SEQ ID NO: 28, SEQ ID NO: 160, SEQ ID NO: 164, SEQ ID NO: 168, SEQ ID NO: 172, SEQ ID NO: 176, SEQ ID NO: 180, SEQ ID NO: 184 and SEQ ID NO: 188. In yet another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence selected from the group of SEQ ID NO: 28, SEQ ID NO: 160, SEQ ID NO: 164, SEQ ID NO: 168, SEQ ID NO: 172, SEQ ID NO: 176, SEQ ID NO: 180, SEQ ID NO: 184 and SEQ ID NO: 188. In another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group of SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 158, SEQ ID NO: 162, SEQ ID NO: 166, SEQ ID NO: 170, SEQ ID NO: 174, SEQ ID NO: 178, SEQ ID NO: 182 and SEQ ID NO: 186. In yet another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence selected from the group of SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 158, SEQ ID NO: 162, SEQ ID NO: 166, SEQ ID NO: 170, SEQ ID NO: 174, SEQ ID NO: 178, SEQ ID NO: 182 and SEQ ID NO: 186.

In yet another embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A2 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification, which in turn shares a carboxy-terminal peptide bond with an IL-10 polypeptide. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 235 or SEQ ID NO: 237, or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A2 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 233 or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises a Fab light chain specific for the A2 domain of Tenascin C. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 239 or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 233, SEQ ID NO: 235 and SEQ ID NO: 239 or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 233, SEQ ID NO: 237 and SEQ ID NO: 239 or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 236 or SEQ ID NO: 238. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 236 or SEQ ID NO: 238. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 234. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 234. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 240. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 240.

In yet another embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A2 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 285, or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for the A2 domain of Tenascin C shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 287, or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises a Fab light chain specific for the A2 domain of Tenascin C. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 239 or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 285, SEQ ID NO: 287 and SEQ ID NO: 239 or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 286. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 286. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 288. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 288. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 240. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 240.

In a particular embodiment, the immunoconjugate comprises at least one, typically two or more antigen binding moieties that are specific for the Fibroblast Activated Protein (FAP). In a specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group consisting of SEQ ID NO: 41, SEQ ID NO: 45, SEQ ID NO: 47, SEQ ID NO: 51, SEQ ID NO: 55, SEQ ID NO: 59, SEQ ID NO: 63, SEQ ID NO: 67, SEQ ID NO: 71, SEQ ID NO: 75, SEQ ID NO: 79, SEQ ID NO: 83, SEQ ID NO: 87, SEQ ID NO: 91, SEQ ID NO: 95, SEQ ID NO: 99, SEQ ID NO: 103, SEQ ID NO: 107, SEQ ID NO: 111, SEQ ID NO: 115, SEQ ID NO: 119, SEQ ID NO: 123, SEQ ID NO: 127, SEQ ID NO: 131, SEQ ID NO: 135, SEQ ID NO: 139, SEQ ID NO: 143, SEQ ID NO: 147, SEQ ID NO: 151 and SEQ ID NO: 155, or variants thereof that retain functionality. In another specific embodiment, the antigen binding moieties of the immunoconjugate comprise a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group consisting of: SEQ ID NO: 37, SEQ ID NO: 39, SEQ ID NO: 43, SEQ ID NO: 49, SEQ ID NO: 53, SEQ ID NO: 57, SEQ ID NO: 61, SEQ ID NO: 65, SEQ ID NO: 69, SEQ ID NO: 73, SEQ ID NO: 77, SEQ ID NO: 81, SEQ ID NO: 85, SEQ ID NO: 89, SEQ ID NO: 93, SEQ ID NO: 97, SEQ ID NO: 101, SEQ ID NO: 105, SEQ ID NO: 109, SEQ ID NO: 113, SEQ ID NO: 117, SEQ ID NO: 121, SEQ ID NO: 125, SEQ ID NO: 129, SEQ ID NO: 133, SEQ ID NO: 137, SEQ ID NO: 141, SEQ ID NO: 145, SEQ ID NO: 149 and SEQ ID NO: 153, or variants thereof that retain functionality. In a more specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group consisting of SEQ ID NO: 41, SEQ ID NO: 45, SEQ ID NO: 47, SEQ ID NO: 51, SEQ ID NO: 55, SEQ ID NO: 59, SEQ ID NO: 63, SEQ ID NO: 67, SEQ ID NO: 71, SEQ ID NO: 75, SEQ ID NO: 79, SEQ ID NO: 83, SEQ ID NO: 87, SEQ ID NO: 91, SEQ ID NO: 95, SEQ ID NO: 99, SEQ ID NO: 103, SEQ ID NO: 107, SEQ ID NO: 111, SEQ ID NO: 115, SEQ ID NO: 119, SEQ ID NO: 123, SEQ ID NO: 127, SEQ ID NO: 131, SEQ ID NO: 135, SEQ ID NO: 139, SEQ ID NO: 143, SEQ ID NO: 147, SEQ ID NO: 151 and SEQ ID NO: 155, or variants thereof that retain functionality, and a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to a sequence selected from the group consisting of: SEQ ID NO: 37, SEQ ID NO: 39, SEQ ID NO: 43, SEQ ID NO: 49, SEQ ID NO: 53, SEQ ID NO: 57, SEQ ID NO: 61, SEQ ID NO: 65, SEQ ID NO: 69, SEQ ID NO: 73, SEQ ID NO: 77, SEQ ID NO: 81, SEQ ID NO: 85, SEQ ID NO: 89, SEQ ID NO: 93, SEQ ID NO: 97, SEQ ID NO: 101, SEQ ID NO: 105, SEQ ID NO: 109, SEQ ID NO: 113, SEQ ID NO: 117, SEQ ID NO: 121, SEQ ID NO: 125, SEQ ID NO: 129, SEQ ID NO: 133, SEQ ID NO: 137, SEQ ID NO: 141, SEQ ID NO: 145, SEQ ID NO: 149 and SEQ ID NO: 153, or variants thereof that retain functionality. In a particular embodiment, the antigen binding moieties of the immunoconjugate comprise the heavy chain variable region sequence of SEQ ID NO: 111 and the light chain variable region sequence of SEQ ID NO: 109. In a further particular embodiment, the antigen binding moieties of the immunoconjugate comprise the heavy chain variable region sequence of SEQ ID NO: 143 and the light chain variable region sequence of SEQ ID NO: 141. In yet another particular embodiment, the antigen binding moieties of the immunoconjugate comprise the heavy chain variable region sequence of SEQ ID NO: 51 and the light chain variable region sequence of SEQ ID NO: 49.

In another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group consisting of: SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 48, SEQ ID NO: 52, SEQ ID NO: 56, SEQ ID NO: 60, SEQ ID NO: 64, SEQ ID NO: 68, SEQ ID NO: 72, SEQ ID NO: 76, SEQ ID NO: 80, SEQ ID NO: 84, SEQ ID NO: 88, SEQ ID NO: 92, SEQ ID NO: 96, SEQ ID NO: 100, SEQ ID NO: 104, SEQ ID NO: 108, SEQ ID NO: 112, SEQ ID NO: 116, SEQ ID NO: 120, SEQ ID NO: 124, SEQ ID NO: 128, SEQ ID NO: 132, SEQ ID NO: 136, SEQ ID NO: 140, SEQ ID NO: 144, SEQ ID NO: 148, SEQ ID NO: 152, and SEQ ID NO: 156. In yet another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence selected from the group consisting of: SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 48, SEQ ID NO: 52, SEQ ID NO: 56, SEQ ID NO: 60, SEQ ID NO: 64, SEQ ID NO: 68, SEQ ID NO: 72, SEQ ID NO: 76, SEQ ID NO: 80, SEQ ID NO: 84, SEQ ID NO: 88, SEQ ID NO: 92, SEQ ID NO: 96, SEQ ID NO: 100, SEQ ID NO: 104, SEQ ID NO: 108, SEQ ID NO: 112, SEQ ID NO: 116, SEQ ID NO: 120, SEQ ID NO: 124, SEQ ID NO: 128, SEQ ID NO: 132, SEQ ID NO: 136, SEQ ID NO: 140, SEQ ID NO: 144, SEQ ID NO: 148, SEQ ID NO: 152, and SEQ ID NO: 156. In another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to sequence selected from the group consisting of: SEQ ID NO: 38, SEQ ID NO: 40, SEQ ID NO: 44, SEQ ID NO: 50, SEQ ID NO: 54, SEQ ID NO: 58, SEQ ID NO: 62, SEQ ID NO: 66, SEQ ID NO: 70, SEQ ID NO: 74, SEQ ID NO: 78, SEQ ID NO: 82, SEQ ID NO: 86, SEQ ID NO: 90, SEQ ID NO: 94, SEQ ID NO: 98, SEQ ID NO: 102, SEQ ID NO: 106, SEQ ID NO: 110, SEQ ID NO: 114, SEQ ID NO: 118, SEQ ID NO: 122, SEQ ID NO: 126, SEQ ID NO: 130, SEQ ID NO: 134, SEQ ID NO: 138, SEQ ID NO: 142, SEQ ID NO: 146, SEQ ID NO: 150, and SEQ ID NO: 154. In yet another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence selected from the group consisting of: SEQ ID NO: 38, SEQ ID NO: 40, SEQ ID NO: 44, SEQ ID NO: 50, SEQ ID NO: 54, SEQ ID NO: 58, SEQ ID NO: 62, SEQ ID NO: 66, SEQ ID NO: 70, SEQ ID NO: 74, SEQ ID NO: 78, SEQ ID NO: 82, SEQ ID NO: 86, SEQ ID NO: 90, SEQ ID NO: 94, SEQ ID NO: 98, SEQ ID NO: 102, SEQ ID NO: 106, SEQ ID NO: 110, SEQ ID NO: 114, SEQ ID NO: 118, SEQ ID NO: 122, SEQ ID NO: 126, SEQ ID NO: 130, SEQ ID NO: 134, SEQ ID NO: 138, SEQ ID NO: 142, SEQ ID NO: 146, SEQ ID NO: 150, and SEQ ID NO: 154.

In one embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In a more specific embodiment, the immunoconjugate comprises a polypeptide sequence selected from the group of SEQ ID NO: 195, SEQ ID NO: 197, SEQ ID NO: 203, SEQ ID NO: 209, SEQ ID NO: 269, SEQ ID NO: 271 and SEQ ID NO: 273, or variants thereof that retain functionality. In one embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-15 polypeptide. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 199, or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment, the immunoconjugate comprises a polypeptide sequence selected from the group of SEQ ID NO: 193, SEQ ID NO: 201 and SEQ ID NO: 207, or variants thereof that retain functionality. In another embodiment, the immunoconjugate comprises a Fab light chain specific for FAP. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 205 or SEQ ID NO: 211, or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 205, the polypeptide sequence of SEQ ID NO: 193, and a polypeptide sequence selected from the group of SEQ ID NO: 195, SEQ ID NO: 197, SEQ ID NO: 199 and SEQ ID NO: 269, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 201, SEQ ID NO: 203 and SEQ ID NO: 205, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 207, SEQ ID NO: 209 and SEQ ID NO: 211, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 205, SEQ ID NO: 193 and SEQ ID NO: 269, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 211, SEQ ID NO: 207 and SEQ ID NO: 271, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 211, SEQ ID NO: 207 and SEQ ID NO: 273, or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In yet another embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification, which in turn shares a carboxy-terminal peptide bond with an IL-10 polypeptide. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 243 or SEQ ID NO: 245, or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 241 or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises a Fab light chain specific for FAP. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 205 or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 205, SEQ ID NO: 241 and SEQ ID NO: 243, or variants thereof that retain functionality. In yet another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 205, SEQ ID NO: 241 and SEQ ID NO: 245, or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group of SEQ ID NO: 196, SEQ ID NO: 198, SEQ ID NO: 200, SEQ ID NO: 204, SEQ ID NO: 210, SEQ ID NO: 244, SEQ ID NO: 246, SEQ ID NO: 270, SEQ ID NO: 272 and SEQ ID NO: 274. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence selected from the group of SEQ ID NO: 196, SEQ ID NO: 198, SEQ ID NO: 200, SEQ ID NO: 204, SEQ ID NO: 210, SEQ ID NO: 244, SEQ ID NO: 246, SEQ ID NO: 270, SEQ ID NO: 272 and SEQ ID NO: 274. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group of SEQ ID NO: 194, SEQ ID NO: 202, SEQ ID NO: 208 and SEQ ID NO: 242. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence selected from the group of SEQ ID NO: 194, SEQ ID NO: 202, SEQ ID NO: 208 and SEQ ID NO: 242. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 206 or SEQ ID NO: 212. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 206 or SEQ ID NO: 212.

In one embodiment, the immunoconjugate comprises at least one, typically two or more antigen binding moieties that are specific for the Carcinoembryonic Antigen (CEA). In a specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 191 or SEQ ID NO: 295, or a variant thereof that retains functionality. In another specific embodiment, the antigen binding moieties of the immunoconjugate comprise a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 189 or SEQ ID NO: 293, or a variant thereof that retains functionality. In a more specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 191, or a variant thereof that retains functionality, and a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 189, or a variant thereof that retains functionality. In another specific embodiment, the antigen binding moieties of the immunoconjugate comprise a heavy chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 295, or a variant thereof that retains functionality, and a light chain variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the sequence of SEQ ID NO: 293, or a variant thereof that retains functionality.

In another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 192 or SEQ ID NO: 296. In yet another specific embodiment, the heavy chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by the polynucleotide sequence of SEQ ID NO: 192 or SEQ ID NO: 296. In another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 190 or SEQ ID NO: 294. In yet another specific embodiment, the light chain variable region sequence of the antigen binding moieties of the immunoconjugate is encoded by the polynucleotide sequence of SEQ ID NO: 190 or SEQ ID NO: 294.

In one embodiment, the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for CEA shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In a more specific embodiment, the immunoconjugate comprises a polypeptide sequence selected from the group consisting of SEQ ID NO: 229, SEQ ID NO: 275, SEQ ID NO: 277 and SEQ ID NO: 279, or a variant thereof that retains functionality. In one embodiment the immunoconjugate comprises a polypeptide sequence wherein a Fab heavy chain specific for CEA shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 227 or SEQ ID NO: 281, or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises a Fab light chain specific for CEA. In a more specific embodiment, the immunoconjugate comprises the polypeptide sequence of SEQ ID NO: 231 or SEQ ID NO: 283, or a variant thereof that retains functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 227, SEQ ID NO: 229 and SEQ ID NO: 231, or variants thereof that retain functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 275, SEQ ID NO: 281 and SEQ ID NO: 283, or variants thereof that retain functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 277, SEQ ID NO: 281 and SEQ ID NO: 283, or variants thereof that retain functionality. In another embodiment, the immunoconjugate comprises the polypeptide sequences of SEQ ID NO: 279, SEQ ID NO: 281 and SEQ ID NO: 283, or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain polypeptide chains comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group consisting of SEQ ID NO: 230, SEQ ID NO: 276, SEQ ID NO: 278 and SEQ ID NO: 280. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence selected from the group consisting of SEQ ID NO: 230, SEQ ID NO: 276, SEQ ID NO: 278 and SEQ ID NO: 280. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 228 or SEQ ID NO: 282. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 228 or SEQ ID NO: 282. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the sequence of SEQ ID NO: 232 or SEQ ID NO: 284. In yet another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence of SEQ ID NO: 232 or SEQ ID NO: 284.

In some embodiments the immunoconjugate comprises a polypeptide sequence wherein an effector moiety polypeptide shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification. In a more specific embodiment, the immunoconjugate comprises a polypeptide sequence selected from the group of SEQ ID NO: 247, SEQ ID NO: 249 and SEQ ID NO: 251, or a variant thereof that retains functionality. In one such embodiment the immunoconjugate further comprises a polypeptide sequence wherein a Fab heavy chain specific for FAP shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment, the immunoconjugate further comprises a polypeptide sequence selected from the group of SEQ ID NO: 193, SEQ ID NO: 201 and SEQ ID NO: 207, or a variant thereof that retains functionality. In another such embodiment the immunoconjugate further comprises a polypeptide sequence wherein a Fab heavy chain specific for EDB, TNC A1, TNC A2 or CEA shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In some embodiments the Fc domain subunits each comprise the amino acid substitutions L234A, L235A, and P329G. According to any of the above embodiments the immunoconjugate may further comprise a Fab light chain specific for the corresponding antigen.

Immunoconjugates of the invention include those that have sequences that are at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the sequences set forth in SEQ ID NOs 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 293, 295, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 269, 271, 273, 275, 277, 279, 281, 283, 285 and 287, including functional fragments or variants thereof. The invention also encompasses immunoconjugates comprising these sequences with conservative amino acid substitutions.

Polynucleotides

The invention further provides isolated polynucleotides encoding an immunoconjugate as described herein or a fragment thereof.

Polynucleotides of the invention include those that are at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the sequences set forth in SEQ ID NOs 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 294, 296, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 270, 272, 274, 276, 278, 280, 282, 284, 286 and 288, including functional fragments or variants thereof.

The polynucleotides encoding immunoconjugates of the invention may be expressed as a single polynucleotide that encodes the entire immunoconjugate or as multiple (e.g., two or more) polynucleotides that are co-expressed. Polypeptides encoded by polynucleotides that are co-expressed may associate through, e.g., disulfide bonds or other means to form a functional immunoconjugate. For example, the light chain portion of an antigen binding moiety may be encoded by a separate polynucleotide from the portion of the immunoconjugate comprising the heavy chain portion of the antigen binding moiety, an Fc domain subunit and optionally the effector moiety. When co-expressed, the heavy chain polypeptides will associate with the light chain polypeptides to form the antigen binding moiety. In another example, the portion of the immunoconjugate comprising the heavy chain portion of a first antigen binding moiety, one of the two Fc domain subunits and the effector moiety could be encoded by a separate polynucleotide from the portion of the immunoconjugate comprising the heavy chain portion of a second antigen binding moiety and the other of the two Fc domain subunits. When co-expressed, the Fc domain subunits will associate to form the Fc domain.

In one embodiment, an isolated polynucleotide of the invention encodes a fragment of an immunoconjugate comprising a first antigen binding moiety, an Fc domain consisting of two subunits, and a single effector moiety, wherein the antigen binding moiety is an antigen binding domain comprising a heavy chain variable region and a light chain variable region, particularly a Fab molecule. In one embodiment, an isolated polynucleotide of the invention encodes the heavy chain of the first antigen binding moiety, a subunit of the Fc domain, and the effector moiety. In another embodiment, an isolated polynucleotide of the invention encodes the heavy chain of the first antigen binding moiety and a subunit of the Fc domain. In yet another embodiment, an isolated polynucleotide of the invention encodes a subunit of the Fc domain and the effector moiety. In a more specific embodiment the isolated polynucleotide encodes a polypeptide wherein a Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit.

In another specific embodiment the isolated polynucleotide encodes a polypeptide wherein an Fc domain subunit shares a carboxy-terminal peptide bond with an effector moiety polypeptide. In yet another specific embodiment, the isolated polynucleotide encodes a polypeptide wherein a Fab heavy chain shares a carboxy-terminal peptide bond with an Fc domain subunit, which in turn shares a carboxy-terminal peptide bond with an effector moiety polypeptide. In yet another specific embodiment the isolated polynucleotide encodes a polypeptide wherein an effector moiety polypeptide shares a carboxy-terminal peptide bond with an Fc domain subunit.

In another embodiment, the present invention is directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that encodes a variable region sequence as shown in SEQ ID NO 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 293 or 295. In another embodiment, the present invention is directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that encodes a polypeptide sequence as shown in SEQ ID NO 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 269, 271, 273, 275, 277, 279, 281, 283, 285 or 287. In another embodiment, the invention is further directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a nucleotide sequence shown SEQ ID NO 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 294, 296, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 270, 272, 274, 276, 278, 280, 282, 284, 286 or 288. In another embodiment, the invention is directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a nucleic acid sequence shown in SEQ ID NO 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 294, 296, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 270, 272, 274, 276, 278, 280, 282, 284, 286 or 288. In another embodiment, the invention is directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that encodes a variable region sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to an amino acid sequence of SEQ ID NO 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51,53, 55, 57, 59, 61,63, 65, 67, 69, 71,73, 75, 77, 79, 81,83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 293 or 295. In another embodiment, the invention is directed to an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that encodes a polypeptide sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to an amino acid sequence of SEQ ID NO 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 269, 271, 273, 275, 277, 279, 281, 283, 285 or 287. The invention encompasses an isolated polynucleotide encoding an immunoconjugate or fragment thereof, wherein the polynucleotide comprises a sequence that encodes the variable region sequences of SEQ ID NO 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51,53, 55, 57, 59, 61,63, 65, 67, 69, 71,73, 75, 77, 79, 81,83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 293 or 295 with conservative amino acid substitutions. The invention also encompasses an isolated polynucleotide encoding an immunoconjugate of the invention or fragment thereof, wherein the polynucleotide comprises a sequence that encodes the polypeptide sequences of SEQ ID NO 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 269, 271, 273, 275, 277, 279, 281, 283, 285 or 287 with conservative amino acid substitutions.

In certain embodiments the polynucleotide or nucleic acid is DNA. In other embodiments, a polynucleotide of the present invention is RNA, for example, in the form of messenger RNA (mRNA). RNA of the present invention may be single stranded or double stranded.

Untargeted Conjugates

The invention provides not only immunoconjugates targeted to a specific antigen (e.g. a tumor antigen) but also untargeted conjugates comprising one or more Fab molecules which do not specifically bind to any antigen, particularly not bind to any human antigen. The absence of specific binding of these conjugates to any antigen (i.e. the absence of any binding that can be discriminated from non-specific interaction) can be measured e.g. by ELISA or surface plasmon resonance as described herein. Such conjugates are particularly useful e.g. for enhancing the serum half life of the effector moiety they comprise, as compared to the serum half-life of the unconjugated effector moiety, where targeting to a particular tissue is not desired.

Specifically, the invention provides a conjugate comprising a first Fab molecule which does not specifically bind any antigen, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. More specifically, the invention provides a conjugate comprising a first Fab molecule comprising the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297, an Fc domain consisting of two subunits, and an effector moiety, wherein not more than one effector moiety is present. Like the immunoconjugates of the invention, the conjugates can have a variety of configurations, as described above under “Immunoconjugate Formats” (the antigen binding moiety of the immunoconjugate being replaced by a Fab molecule which does not specifically bind to any antigen, such as a Fab molecule comprising the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297). Likewise, the features of the Fc domain as well as the effector moiety as described above under “Fc domain” and “Effector moieties” for the immunoconjugates of the invention equally apply, alone or in combination, to the untargeted conjugates of the invention.

In a particular embodiment, the conjugate comprises (i) an immunoglobulin molecule, comprising a first and a second Fab molecule which do not specifically bind any antigen and an Fc domain, and (ii) an effector moiety, wherein not more than one effector moiety is present and wherein the immunoglobulin molecule is a human IgG1 subclass immunoglobulin; the Fc domain comprises a knob modification in one and a hole modification in the other one of its two subunits, and the amino acid substitutions L234A, L235A and P329G in each of its subunits; and the effector moiety is an IL-2 molecule fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, optionally through a linker peptide. In a specific embodiment, the conjugate comprises the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297.

In certain embodiments, the conjugate comprises (i) an immunoglobulin molecule, comprising the heavy chain variable region sequence of SEQ ID NO: 299 and the light chain variable region sequence of SEQ ID NO: 297, and (ii) an effector moiety, wherein not more than one effector moiety is present. In one such embodiment the immunoglobulin molecule is a human IgG1 subclass immunoglobulin. In one such embodiment the Fc domain comprises a knob modification in one and a hole modification in the other one of its two subunits. In a specific such embodiment, the Fc domain comprises the amino acid substitutions L234A, L235A and P329G in each of its subunits. In yet another such embodiment, the effector moiety is an IL-2 molecule fused to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains, optionally through a linker peptide.

In one embodiment the conjugate comprises a polypeptide sequence wherein a Fab heavy chain which does not specifically bind to any antigen shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a knob modification, which in turn shares a carboxy-terminal peptide bond with an IL-2 polypeptide. In a more specific embodiment, the conjugate comprises a polypeptide sequence selected from the group of SEQ ID NO: 221, SEQ ID NO: 223, SEQ ID NO: 289 and SEQ ID NO: 291, or a variant thereof that retains functionality. In one embodiment the conjugate comprises a polypeptide sequence wherein a Fab heavy chain which does not specifically bind to any antigen shares a carboxy-terminal peptide bond with an Fc domain subunit comprising a hole modification. In a more specific embodiment, the conjugate comprises the polypeptide sequence of SEQ ID NO: 219, or a variant thereof that retains functionality. In another embodiment, the conjugate comprises a Fab light chain which does not specifically bind any antigen. In a more specific embodiment, the conjugate comprises the polypeptide sequence of SEQ ID NO: 225, or a variant thereof that retains functionality. In another embodiment, the conjugate comprises the polypeptide sequences of SEQ ID NO: 219, SEQ ID NO: 221 and SEQ ID NO: 225, or variants thereof that retain functionality. In another embodiment, the conjugate comprises the polypeptide sequences of SEQ ID NO: 219, SEQ ID NO: 223 and SEQ ID NO: 225, or variants thereof that retain functionality. In another embodiment, the conjugate comprises the polypeptide sequences of SEQ ID NO: 219, SEQ ID NO: 289 and SEQ ID NO: 225, or variants thereof that retain functionality. In another embodiment, the conjugate comprises the polypeptide sequences of SEQ ID NO: 219, SEQ ID NO: 291 and SEQ ID NO: 225, or variants thereof that retain functionality. In another specific embodiment, the polypeptides are covalently linked, e.g., by a disulfide bond. In some embodiments the Fc domain polypeptide chains comprise the amino acid substitutions L234A, L235A, and P329G.

In a specific embodiment, the conjugate comprises a polypeptide sequence encoded by a polynucleotide sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a sequence selected from the group consisting of SEQ ID NO: 298, SEQ ID NO: 300, SEQ ID NO: 220, SEQ ID NO: 222, SEQ ID NO: 224, SEQ ID NO: 226, SEQ ID NO: 290 and SEQ ID NO: 292. In another specific embodiment, the immunoconjugate comprises a polypeptide sequence encoded by the polynucleotide sequence selected from the group consisting of SEQ ID NO: 298, SEQ ID NO: 300, SEQ ID NO: 220, SEQ ID NO: 222, SEQ ID NO: 224, SEQ ID NO: 226, SEQ ID NO: 290 and SEQ ID NO: 292.

The invention also provides an isolated polynucleotide encoding the conjugate of the invention of a fragment thereof. In a specific embodiment, the isolated polynucleotide comprises a sequence that is at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to the a sequence selected from the group of SEQ ID NO: 298, SEQ ID NO: 300, SEQ ID NO: 220, SEQ ID NO: 222, SEQ ID NO: 224, SEQ ID NO: 226, SEQ ID NO: 290 and SEQ ID NO: 292. The invention further provides an expression vector comprising the isolated polynucleotide, and a host cell comprising the isolated polynucleotide or the expression vector of the invention. In another aspect is provided a method of producing the conjugate of the invention, comprising the steps of a) culturing the host cell of the invention under conditions suitable for the expression of the conjugate and b) recovering the conjugate. The invention also encompasses a conjugate produced by the method of the invention. The disclosure provided herein in relating to methods of producing the immunoconjugates of the invention (see e.g. under “Recombinant Methods”) can equally be applied to the conjugates of the invention.

The invention further provides a pharmaceutical composition comprising the conjugate of the invention and a pharmaceutically acceptable carrier. The disclosure provided herein in relating to pharmaceutical compositions of the immunoconjugates of the invention (see e.g. under “Compositions, Formulations, and Routes of Administration”) can equally be applied to the conjugates of the invention. Furthermore, the conjugate can be employed in the methods of use described herein for the immunoconjugates of the invention. The disclosure provided herein in relating to methods of using the immunoconjugates of the invention in the treatment of disease (see e.g. under “Therapeutic Methods and Compositions”, “Other Agents and Treatments” and “Articles of manufacture”) can equally be applied to the conjugates of the invention.

Recombinant Methods

Immunoconjugates of the invention may be obtained, for example, by solid-state peptide synthesis (e.g. Merrifield solid phase synthesis) or recombinant production. For recombinant production one or more polynucleotide encoding the immunoconjugate (fragment), e.g., as described above, is isolated and inserted into one or more vectors for further cloning and/or expression in a host cell. Such polynucleotide may be readily isolated and sequenced using conventional procedures. In one embodiment a vector, preferably an expression vector, comprising one or more of the polynucleotides of the invention is provided. Methods which are well known to those skilled in the art can be used to construct expression vectors containing the coding sequence of an immunoconjugate (fragment) along with appropriate transcriptional/translational control signals. These methods include in vitro recombinant DNA techniques, synthetic techniques and in vivo recombination/genetic recombination. See, for example, the techniques described in Maniatis et al., MOLECULAR CLONING: A LABORATORY MANUAL, Cold Spring Harbor Laboratory, N.Y. (1989); and Ausubel et al., CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, Greene Publishing Associates and Wiley Interscience, N.Y (1989). The expression vector can be part of a plasmid, virus, or may be a nucleic acid fragment. The expression vector includes an expression cassette into which the polynucleotide encoding the immunoconjugate (fragment) (i.e. the coding region) is cloned in operable association with a promoter and/or other transcription or translation control elements. As used herein, a “coding region” is a portion of nucleic acid which consists of codons translated into amino acids. Although a “stop codon” (TAG, TGA, or TAA) is not translated into an amino acid, it may be considered to be part of a coding region, if present, but any flanking sequences, for example promoters, ribosome binding sites, transcriptional terminators, introns, 5′ and 3′ untranslated regions, and the like, are not part of a coding region. Two or more coding regions can be present in a single polynucleotide construct, e.g. on a single vector, or in separate polynucleotide constructs, e.g. on separate (different) vectors. Furthermore, any vector may contain a single coding region, or may comprise two or more coding regions, e.g. a vector of the present invention may encode one or more polypeptides, which are post- or co-translationally separated into the final proteins via proteolytic cleavage. In addition, a vector, polynucleotide, or nucleic acid of the invention may encode heterologous coding regions, either fused or unfused to a polynucleotide encoding the immunoconjugate (fragment) of the invention, or variant or derivative thereof. Heterologous coding regions include without limitation specialized elements or motifs, such as a secretory signal peptide or a heterologous functional domain. An operable association is when a coding region for a gene product, e.g. a polypeptide, is associated with one or more regulatory sequences in such a way as to place expression of the gene product under the influence or control of the regulatory sequence(s). Two DNA fragments (such as a polypeptide coding region and a promoter associated therewith) are “operably associated” if induction of promoter function results in the transcription of mRNA encoding the desired gene product and if the nature of the linkage between the two DNA fragments does not interfere with the ability of the expression regulatory sequences to direct the expression of the gene product or interfere with the ability of the DNA template to be transcribed. Thus, a promoter region would be operably associated with a nucleic acid encoding a polypeptide if the promoter was capable of effecting transcription of that nucleic acid. The promoter may be a cell-specific promoter that directs substantial transcription of the DNA only in predetermined cells. Other transcription control elements, besides a promoter, for example enhancers, operators, repressors, and transcription termination signals, can be operably associated with the polynucleotide to direct cell-specific transcription. Suitable promoters and other transcription control regions are disclosed herein. A variety of transcription control regions are known to those skilled in the art. These include, without limitation, transcription control regions, which function in vertebrate cells, such as, but not limited to, promoter and enhancer segments from cytomegaloviruses (e.g. the immediate early promoter, in conjunction with intron-A), simian virus 40 (e.g. the early promoter), and retroviruses (such as, e.g. Rous sarcoma virus). Other transcription control regions include those derived from vertebrate genes such as actin, heat shock protein, bovine growth hormone and rabbit â-globin, as well as other sequences capable of controlling gene expression in eukaryotic cells. Additional suitable transcription control regions include tissue-specific promoters and enhancers as well as inducible promoters (e.g. promoters inducible tetracyclins). Similarly, a variety of translation control elements are known to those of ordinary skill in the art. These include, but are not limited to ribosome binding sites, translation initiation and termination codons, and elements derived from viral systems (particularly an internal ribosome entry site, or IRES, also referred to as a CITE sequence). The expression cassette may also include other features such as an origin of replication, and/or chromosome integration elements such as retroviral long terminal repeats (LTRs), or adeno-associated viral (AAV) inverted terminal repeats (ITRs).

Polynucleotide and nucleic acid coding regions of the present invention may be associated with additional coding regions which encode secretory or signal peptides, which direct the secretion of a polypeptide encoded by a polynucleotide of the present invention. For example, if secretion of the immunoconjugate is desired, DNA encoding a signal sequence may be placed upstream of the nucleic acid encoding an immunoconjugates of the invention or a fragment thereof. According to the signal hypothesis, proteins secreted by mammalian cells have a signal peptide or secretory leader sequence which is cleaved from the mature protein once export of the growing protein chain across the rough endoplasmic reticulum has been initiated. Those of ordinary skill in the art are aware that polypeptides secreted by vertebrate cells generally have a signal peptide fused to the N-terminus of the polypeptide, which is cleaved from the translated polypeptide to produce a secreted or “mature” form of the polypeptide. In certain embodiments, the native signal peptide, e.g. an immunoglobulin heavy chain or light chain signal peptide is used, or a functional derivative of that sequence that retains the ability to direct the secretion of the polypeptide that is operably associated with it. Alternatively, a heterologous mammalian signal peptide, or a functional derivative thereof, may be used. For example, the wild-type leader sequence may be substituted with the leader sequence of human tissue plasminogen activator (TPA) or mouse β-glucuronidase. Exemplary amino acid and corresponding polynucleotide sequences of secretory signal peptides are shown in SEQ ID NOs 8-16.

DNA encoding a short protein sequence that could be used to facilitate later purification (e.g. a histidine tag) or assist in labeling the immunoconjugate may be included within or at the ends of the immunoconjugate (fragment) encoding polynucleotide.

In a further embodiment, a host cell comprising one or more polynucleotides of the invention is provided. In certain embodiments a host cell comprising one or more vectors of the invention is provided. The polynucleotides and vectors may incorporate any of the features, singly or in combination, described herein in relation to polynucleotides and vectors, respectively. In one such embodiment a host cell comprises (e.g. has been transformed or transfected with) a vector comprising a polynucleotide that encodes (part of) an immunoconjugate of the invention. As used herein, the term “host cell” refers to any kind of cellular system which can be engineered to generate the immunoconjugates of the invention or fragments thereof. Host cells suitable for replicating and for supporting expression of immunoconjugates are well known in the art. Such cells may be transfected or transduced as appropriate with the particular expression vector and large quantities of vector containing cells can be grown for seeding large scale fermenters to obtain sufficient quantities of the immunoconjugate for clinical applications. Suitable host cells include prokaryotic microorganisms, such as E. coli, or various eukaryotic cells, such as Chinese hamster ovary cells (CHO), insect cells, or the like. For example, polypeptides may be produced in bacteria in particular when glycosylation is not needed. After expression, the polypeptide may be isolated from the bacterial cell paste in a soluble fraction and can be further purified. In addition to prokaryotes, eukaryotic microbes such as filamentous fungi or yeast are suitable cloning or expression hosts for polypeptide-encoding vectors, including fungi and yeast strains whose glycosylation pathways have been “humanized”, resulting in the production of a polypeptide with a partially or fully human glycosylation pattern. See Gerngross, Nat Biotech 22, 1409-1414 (2004), and Li et al., Nat Biotech 24, 210-215 (2006). Suitable host cells for the expression of (glycosylated) polypeptides are also derived from multicellular organisms (invertebrates and vertebrates). Examples of invertebrate cells include plant and insect cells. Numerous baculoviral strains have been identified which may be used in conjunction with insect cells, particularly for transfection of Spodoptera frugiperda cells. Plant cell cultures can also be utilized as hosts. See e.g. U.S. Pat. Nos. 5,959,177, 6,040,498, 6,420,548, 7,125,978, and 6,417,429 (describing PLANTIBODIES™ technology for producing antibodies in transgenic plants). Vertebrate cells may also be used as hosts. For example, mammalian cell lines that are adapted to grow in suspension may be useful. Other examples of useful mammalian host cell lines are monkey kidney CV1 line transformed by SV40 (COS-7); human embryonic kidney line (293 or 293T cells as described, e.g., in Graham et al., J Gen Virol 36, 59 (1977)), baby hamster kidney cells (BHK), mouse sertoli cells (TM4 cells as described, e.g., in Mather, Biol Reprod 23, 243-251 (1980)), monkey kidney cells (CV1), African green monkey kidney cells (VERO-76), human cervical carcinoma cells (HELA), canine kidney cells (MDCK), buffalo rat liver cells (BRL 3A), human lung cells (W138), human liver cells (Hep G2), mouse mammary tumor cells (MMT 060562), TRI cells (as described, e.g., in Mather et al., Annals N.Y. Acad Sci 383, 44-68 (1982)), MRC 5 cells, and FS4 cells. Other useful mammalian host cell lines include Chinese hamster ovary (CHO) cells, including dhff CHO cells (Urlaub et al., Proc Natl Acad Sci USA 77, 4216 (1980)); and myeloma cell lines such as YO, NS0, P3X63 and Sp2/0. For a review of certain mammalian host cell lines suitable for protein production, see, e.g., Yazaki and Wu, Methods in Molecular Biology, Vol. 248 (B.K.C. Lo, ed., Humana Press, Totowa, N.J.), pp. 255-268 (2003). Host cells include cultured cells, e.g., mammalian cultured cells, yeast cells, insect cells, bacterial cells and plant cells, to name only a few, but also cells comprised within a transgenic animal, transgenic plant or cultured plant or animal tissue. In one embodiment, the host cell is a eukaryotic cell, preferably a mammalian cell, such as a Chinese Hamster Ovary (CHO) cell, a human embryonic kidney (HEK) cell or a lymphoid cell (e.g., Y0, NS0, Sp20 cell). Standard technologies are known in the art to express foreign genes in these systems. Cells expressing a polypeptide comprising either the heavy or the light chain of an antigen binding domain such as an antibody, may be engineered so as to also express the other of the antibody chains such that the expressed product is an antibody that has both a heavy and a light chain.

In one embodiment, a method of producing an immunoconjugate according to the invention is provided, wherein the method comprises culturing a host cell comprising a polynucleotide encoding the immunoconjugate, as provided herein, under conditions suitable for expression of the immunoconjugate, and recovering the immunoconjugate from the host cell (or host cell culture medium).

The components of the immunoconjugate are genetically fused to each other. Immunoconjugates can be designed such that its components are fused directly to each other or indirectly through a linker sequence. The composition and length of the linker may be determined in accordance with methods well known in the art and may be tested for efficacy. Examples of linker sequences between the effector moiety and the Fc domain are found in the sequences shown in SEQ ID NO 195, 197, 199, 203, 209, 215, 229, 235, 237, 243, 245, 247, 249, 251, 269, 271, 273, 275, 277, 279 and 285. Additional sequences may also be included to incorporate a cleavage site to separate the individual components of the fusion if desired, for example an endopeptidase recognition sequence.

In certain embodiments the one or more antigen binding moieties of the immunoconjugate comprise at least an antibody variable region capable of binding an antigenic determinant. Variable regions can form part of and be derived from naturally or non-naturally occurring antibodies and fragments thereof. Methods to produce polyclonal antibodies and monoclonal antibodies are well known in the art (see e.g. Harlow and Lane, “Antibodies, a laboratory manual”, Cold Spring Harbor Laboratory, 1988). Non-naturally occurring antibodies can be constructed using solid phase-peptide synthesis, can be produced recombinantly (e.g. as described in U.S. Pat. No. 4,186,567) or can be obtained, for example, by screening combinatorial libraries comprising variable heavy chains and variable light chains (see e.g. U.S. Pat. No. 5,969,108 to McCafferty). Antigen binding moieties and methods for producing the same are also described in detail in PCT publication WO 2011/020783, the entire content of which is incorporated herein by reference.

Any animal species of antibody, antibody fragment, antigen binding domain or variable region can be used in the immunoconjugates of the invention. Non-limiting antibodies, antibody fragments, antigen binding domains or variable regions useful in the present invention can be of murine, primate, or human origin. If the immunoconjugate is intended for human use, a chimeric form of antibody may be used wherein the constant regions of the antibody are from a human. A humanized or fully human form of the antibody can also be prepared in accordance with methods well known in the art (see e.g. U.S. Pat. No. 5,565,332 to Winter). Humanization may be achieved by various methods including, but not limited to (a) grafting the non-human (e.g., donor antibody) CDRs onto human (e.g. recipient antibody) framework and constant regions with or without retention of critical framework residues (e.g. those that are important for retaining good antigen binding affinity or antibody functions), (b) grafting only the non-human specificity-determining regions (SDRs or a-CDRs; the residues critical for the antibody-antigen interaction) onto human framework and constant regions, or (c) transplanting the entire non-human variable domains, but “cloaking” them with a human-like section by replacement of surface residues. Humanized antibodies and methods of making them are reviewed, e.g., in Almagro and Fransson, Front Biosci 13, 1619-1633 (2008), and are further described, e.g., in Riechmann et al., Nature 332, 323-329 (1988); Queen et al., Proc Natl Acad Sci USA 86, 10029-10033 (1989); U.S. Pat. Nos. 5,821,337, 7,527,791, 6,982,321, and 7,087,409; Jones et al., Nature 321, 522-525 (1986); Morrison et al., Proc Natl Acad Sci 81, 6851-6855 (1984); Morrison and Oi, Adv Immunol 44, 65-92 (1988); Verhoeyen et al., Science 239, 1534-1536 (1988); Padlan, Molec Immun 31(3), 169-217 (1994); Kashmiri et al., Methods 36, 25-34 (2005) (describing SDR (a-CDR) grafting); Padlan, Mol Immunol 28, 489-498 (1991) (describing “resurfacing”); Dall'Acqua et al., Methods 36, 43-60 (2005) (describing “FR shuffling”); and Osbourn et al., Methods 36, 61-68 (2005) and Klimka et al., Br J Cancer 83, 252-260 (2000) (describing the “guided selection” approach to FR shuffling). Human antibodies and human variable regions can be produced using various techniques known in the art. Human antibodies are described generally in van Dijk and van de Winkel, Curr Opin Pharmacol 5, 368-74 (2001) and Lonberg, Curr Opin Immunol 20, 450-459 (2008). Human variable regions can form part of and be derived from human monoclonal antibodies made by the hybridoma method (see e.g. Monoclonal Antibody Production Techniques and Applications, pp. 51-63 (Marcel Dekker, Inc., New York, 1987)). Human antibodies and human variable regions may also be prepared by administering an immunogen to a transgenic animal that has been modified to produce intact human antibodies or intact antibodies with human variable regions in response to antigenic challenge (see e.g. Lonberg, Nat Biotech 23, 1117-1125 (2005). Human antibodies and human variable regions may also be generated by isolating Fv clone variable region sequences selected from human-derived phage display libraries (see e.g., Hoogenboom et al. in Methods in Molecular Biology 178, 1-37 (O'Brien et al., ed., Human Press, Totowa, N.J., 2001); and McCafferty et al., Nature 348, 552-554; Clackson et al., Nature 352, 624-628 (1991)). Phage typically display antibody fragments, either as single-chain Fv (scFv) fragments or as Fab fragments. A detailed description of the preparation of antigen binding moieties for immunoconjugates by phage display can be found in the Examples appended to PCT publication WO 2011/020783.

In certain embodiments, the antigen binding moieties useful in the present invention are engineered to have enhanced binding affinity according to, for example, the methods disclosed in PCT publication WO 2011/020783 (see Examples relating to affinity maturation) or U.S. Pat. Appl. Publ. No. 2004/0132066, the entire contents of which are hereby incorporated by reference. The ability of the immunoconjugate of the invention to bind to a specific antigenic determinant can be measured either through an enzyme-linked immunosorbent assay (ELISA) or other techniques familiar to one of skill in the art, e.g. surface plasmon resonance technique (analyzed on a BIACORE T100 system) (Liljeblad, et al., Glyco J 17, 323-329 (2000)), and traditional binding assays (Heeley, Endocr Res 28, 217-229 (2002)). Competition assays may be used to identify an antibody, antibody fragment, antigen binding domain or variable domain that competes with a reference antibody for binding to a particular antigen, e.g. an antibody that competes with the L19 antibody for binding to the Extra Domain B of fibronectin (EDB). In certain embodiments, such a competing antibody binds to the same epitope (e.g. a linear or a conformational epitope) that is bound by the reference antibody. Detailed exemplary methods for mapping an epitope to which an antibody binds are provided in Morris (1996) “Epitope Mapping Protocols,” in Methods in Molecular Biology vol. 66 (Humana Press, Totowa, N.J.). In an exemplary competition assay, immobilized antigen (e.g. EDB) is incubated in a solution comprising a first labeled antibody that binds to the antigen (e.g. L19 antibody) and a second unlabeled antibody that is being tested for its ability to compete with the first antibody for binding to the antigen. The second antibody may be present in a hybridoma supernatant. As a control, immobilized antigen is incubated in a solution comprising the first labeled antibody but not the second unlabeled antibody. After incubation under conditions permissive for binding of the first antibody to the antigen, excess unbound antibody is removed, and the amount of label associated with immobilized antigen is measured. If the amount of label associated with immobilized antigen is substantially reduced in the test sample relative to the control sample, then that indicates that the second antibody is competing with the first antibody for binding to the antigen. See Harlow and Lane (1988) Antibodies: A Laboratory Manual ch. 14 (Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.).

Immunoconjugates prepared as described herein may be purified by art-known techniques such as high performance liquid chromatography, ion exchange chromatography, gel electrophoresis, affinity chromatography, size exclusion chromatography, and the like. The actual conditions used to purify a particular protein will depend, in part, on factors such as net charge, hydrophobicity, hydrophilicity etc., and will be apparent to those having skill in the art. For affinity chromatography purification an antibody, ligand, receptor or antigen can be used to which the immunoconjugate binds. For example, for affinity chromatography purification of immunoconjugates of the invention, a matrix with protein A or protein G may be used. Sequential Protein A or G affinity chromatography and size exclusion chromatography can be used to isolate an immunoconjugate essentially as described in the Examples. The purity of the immunoconjugate can be determined by any of a variety of well known analytical methods including gel electrophoresis, high pressure liquid chromatography, and the like. For example, the heavy chain fusion proteins expressed as described in the Examples were shown to be intact and properly assembled as demonstrated by reducing SDS-PAGE (see e.g. FIGS. 4A-D). Three bands were resolved at approximately Mr 25,000, Mr 50,000 and Mr 60,000, corresponding to the predicted molecular weights of the immunoglobulin light chain, heavy chain and heavy chain/effector moiety fusion protein.

Assays

Immunoconjugates provided herein may be identified, screened for, or characterized for their physical/chemical properties and/or biological activities by various assays known in the art.

Affinity Assays

The affinity of the immunoconjugate for an effector moiety receptor (e.g. IL-10R or various forms of IL-2R), an Fc receptor, or a target antigen, can be determined in accordance with the methods set forth in the Examples by surface plasmon resonance (SPR), using standard instrumentation such as a BIAcore instrument (GE Healthcare), and receptors or target proteins such as may be obtained by recombinant expression. Alternatively, binding of immunoconjugates for different receptors or target antigens may be evaluated using cell lines expressing the particular receptor or target antigen, for example by flow cytometry (FACS). A specific illustrative and exemplary embodiment for measuring binding affinity is described in the following and in the Examples below.

According to one embodiment, K_(D) is measured by surface plasmon resonance using a BIACORE® T100 machine (GE Healthcare) at 25° C. with ligand (e.g. effector moiety receptor, Fc receptor or target antigen) immobilized on CMS chips. Briefly, carboxymethylated dextran biosensor chips (CMS, GE Healthcare) are activated with N-ethyl-N′-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) according to the supplier's instructions. Recombinant ligand is diluted with 10 mM sodium acetate, pH 5.5, to 0.5-30 μg/ml before injection at a flow rate of 10 μl/minute to achieve approximately 100-5000 response units (RU) of coupled protein. Following the injection of the ligand, 1 M ethanolamine is injected to block unreacted groups. For kinetics measurements, three- to five-fold serial dilutions of immunoconjugate (range between ˜0.01 nM to 300 nM) are injected in HBS-EP+(GE Healthcare, 10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05% Surfactant P20, pH 7.4) at 25° C. at a flow rate of approximately 30-50 μl/min. Association rates (k_(on)) and dissociation rates (kw) are calculated using a simple one-to-one Langmuir binding model (BIACORE® T100 Evaluation Software version 1.1.1) by simultaneously fitting the association and dissociation sensorgrams. The equilibrium dissociation constant (K_(D)) is calculated as the ratio k_(off)/k_(on). See, e.g., Chen et al., J Mol Biol 293, 865-881 (1999).

Activity Assays

Biological activity of the immunoconjugates of the invention can be measured by various assays as described in the Examples. Biological activities may for example include the induction of proliferation of effector moiety receptor-bearing cells, the induction of signaling in effector moiety receptor-bearing cells, the induction of cytokine secretion by effector moiety receptor-bearing cells, and the induction of tumor regression and/or the improvement of survival.

Compositions, Formulations, and Routes of Administration

In a further aspect, the invention provides pharmaceutical compositions comprising any of the immunoconjugates provided herein, e.g., for use in any of the below therapeutic methods. In one embodiment, a pharmaceutical composition comprises any of the immunoconjugates provided herein and a pharmaceutically acceptable carrier. In another embodiment, a pharmaceutical composition comprises any of the immunoconjugates provided herein and at least one additional therapeutic agent, e.g., as described below.

Further provided is a method of producing an immunoconjugate of the invention in a form suitable for administration in vivo, the method comprising (a) obtaining an immunoconjugate according to the invention, and (b) formulating the immunoconjugate with at least one pharmaceutically acceptable carrier, whereby a preparation of immunoconjugate is formulated for administration in vivo.

Pharmaceutical compositions of the present invention comprise a therapeutically effective amount of one or more immunoconjugate dissolved or dispersed in a pharmaceutically acceptable carrier. The phrases “pharmaceutical or pharmacologically acceptable” refers to molecular entities and compositions that are generally non-toxic to recipients at the dosages and concentrations employed, i.e. do not produce an adverse, allergic or other untoward reaction when administered to an animal, such as, for example, a human, as appropriate. The preparation of a pharmaceutical composition that contains at least one immunoconjugate and optionally an additional active ingredient will be known to those of skill in the art in light of the present disclosure, as exemplified by Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, incorporated herein by reference. Moreover, for animal (e.g., human) administration, it will be understood that preparations should meet sterility, pyrogenicity, general safety and purity standards as required by FDA Office of Biological Standards or corresponding authorities in other countries. Preferred compositions are lyophilized formulations or aqueous solutions. As used herein, “pharmaceutically acceptable carrier” includes any and all solvents, buffers, dispersion media, coatings, surfactants, antioxidants, preservatives (e.g. antibacterial agents, antifungal agents), isotonic agents, absorption delaying agents, salts, preservatives, antioxidants, proteins, drugs, drug stabilizers, polymers, gels, binders, excipients, disintegration agents, lubricants, sweetening agents, flavoring agents, dyes, such like materials and combinations thereof, as would be known to one of ordinary skill in the art (see, for example, Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, pp. 1289-1329, incorporated herein by reference). Except insofar as any conventional carrier is incompatible with the active ingredient, its use in the therapeutic or pharmaceutical compositions is contemplated.

The composition may comprise different types of carriers depending on whether it is to be administered in solid, liquid or aerosol form, and whether it need to be sterile for such routes of administration as injection. Immunoconjugates of the present invention (and any additional therapeutic agent) can be administered intravenously, intradermally, intraarterially, intraperitoneally, intralesionally, intracranially, intraarticularly, intraprostatically, intrasplenically, intrarenally, intrapleurally, intratracheally, intranasally, intravitreally, intravaginally, intrarectally, intratumorally, intramuscularly, intraperitoneally, subcutaneously, subconjunctivally, intravesicularlly, mucosally, intrapericardially, intraumbilically, intraocularally, orally, topically, locally, by inhalation (e.g. aerosol inhalation), injection, infusion, continuous infusion, localized perfusion bathing target cells directly, via a catheter, via a lavage, in cremes, in lipid compositions (e.g. liposomes), or by other method or any combination of the forgoing as would be known to one of ordinary skill in the art (see, for example, Remington's Pharmaceutical Sciences, 18th Ed. Mack Printing Company, 1990, incorporated herein by reference). Parenteral administration, in particular intravenous injection, is most commonly used for administering polypeptide molecules such as the immunoconjugates of the invention.

Parenteral compositions include those designed for administration by injection, e.g. subcutaneous, intradermal, intralesional, intravenous, intraarterial intramuscular, intrathecal or intraperitoneal injection. For injection, the immunoconjugates of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks' solution, Ringer's solution, or physiological saline buffer. The solution may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the immunoconjugates may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use. Sterile injectable solutions are prepared by incorporating the immunoconjugates of the invention in the required amount in the appropriate solvent with various of the other ingredients enumerated below, as required. Sterility may be readily accomplished, e.g., by filtration through sterile filtration membranes. Generally, dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle which contains the basic dispersion medium and/or the other ingredients. In the case of sterile powders for the preparation of sterile injectable solutions, suspensions or emulsion, the preferred methods of preparation are vacuum-drying or freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered liquid medium thereof. The liquid medium should be suitably buffered if necessary and the liquid diluent first rendered isotonic prior to injection with sufficient saline or glucose. The composition must be stable under the conditions of manufacture and storage, and preserved against the contaminating action of microorganisms, such as bacteria and fungi. It will be appreciated that endotoxin contamination should be kept minimally at a safe level, for example, less that 0.5 ng/mg protein. Suitable pharmaceutically acceptable carriers include, but are not limited to: buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride; benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g. Zn-protein complexes); and/or non-ionic surfactants such as polyethylene glycol (PEG). Aqueous injection suspensions may contain compounds which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, dextran, or the like. Optionally, the suspension may also contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl cleats or triglycerides, or liposomes.

Active ingredients may be entrapped in microcapsules prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences (18th Ed. Mack Printing Company, 1990). Sustained-release preparations may be prepared. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the polypeptide, which matrices are in the form of shaped articles, e.g. films, or microcapsules. In particular embodiments, prolonged absorption of an injectable composition can be brought about by the use in the compositions of agents delaying absorption, such as, for example, aluminum monostearate, gelatin or combinations thereof.

In addition to the compositions described previously, the immunoconjugates may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the immunoconjugates may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

Pharmaceutical compositions comprising the immunoconjugates of the invention may be manufactured by means of conventional mixing, dissolving, emulsifying, encapsulating, entrapping or lyophilizing processes. Pharmaceutical compositions may be formulated in conventional manner using one or more physiologically acceptable carriers, diluents, excipients or auxiliaries which facilitate processing of the proteins into preparations that can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.

The immunoconjugates may be formulated into a composition in a free acid or base, neutral or salt form. Pharmaceutically acceptable salts are salts that substantially retain the biological activity of the free acid or base. These include the acid addition salts, e.g., those formed with the free amino groups of a proteinaceous composition, or which are formed with inorganic acids such as for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric or mandelic acid. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as for example, sodium, potassium, ammonium, calcium or ferric hydroxides; or such organic bases as isopropylamine, trimethylamine, histidine or procaine. Pharmaceutical salts tend to be more soluble in aqueous and other protic solvents than are the corresponding free base forms.

Therapeutic Methods and Compositions

Any of the immunoconjugates provided herein may be used in therapeutic methods. Immunoconjugates of the invention can be used as immunotherapeutic agents, for example in the treatment of cancers.

For use in therapeutic methods, immunoconjugates of the invention would be formulated, dosed, and administered in a fashion consistent with good medical practice. Factors for consideration in this context include the particular disorder being treated, the particular mammal being treated, the clinical condition of the individual patient, the cause of the disorder, the site of delivery of the agent, the method of administration, the scheduling of administration, and other factors known to medical practitioners.

In one aspect, immunoconjugates of the invention for use as a medicament are provided. In further aspects, immunoconjugates of the invention for use in treating a disease are provided. In certain embodiments, immunoconjugates of the invention for use in a method of treatment are provided. In one embodiment, the invention provides an immunoconjugate as described herein for use in the treatment of a disease in an individual in need thereof. In certain embodiments, the invention provides an immunoconjugate for use in a method of treating an individual having a disease comprising administering to the individual a therapeutically effective amount of the immunoconjugate. In certain embodiments the disease to be treated is a proliferative disorder. In a particular embodiment the disease is cancer. In other embodiments the disease to be treated is an inflammatory disorder. In certain embodiments the method further comprises administering to the individual a therapeutically effective amount of at least one additional therapeutic agent, e.g., an anti-cancer agent if the disease to be treated is cancer. An “individual” according to any of the above embodiments is a mammal, preferably a human.

In a further aspect, the invention provides for the use of an immunconjugate of the invention in the manufacture or preparation of a medicament for the treatment of a disease in an individual in need thereof. In one embodiment, the medicament is for use in a method of treating a disease comprising administering to an individual having the disease a therapeutically effective amount of the medicament. In certain embodiments the disease to be treated is a proliferative disorder. In a particular embodiment the disease is cancer. In other embodiments the disease to be treated is an inflammatory disorder. In one embodiment, the method further comprises administering to the individual a therapeutically effective amount of at least one additional therapeutic agent, e.g., an anti-cancer agent if the disease to be treated is cancer. An “individual” according to any of the above embodiments may be a mammal, preferably a human.

In a further aspect, the invention provides a method for treating a disease in an individual, comprising administering to said individual a therapeutically effective amount of an immunoconjugate of the invention. In one embodiment a composition is administered to said individual, comprising immunoconjugate of the invention in a pharmaceutically acceptable form.

In certain embodiments the disease to be treated is a proliferative disorder. In a particular embodiment the disease is cancer. In other embodiments the disease to be treated is an inflammatory disorder. In certain embodiments the method further comprises administering to the individual a therapeutically effective amount of at least one additional therapeutic agent, e.g., an anti-cancer agent if the disease to be treated is cancer. An “individual” according to any of the above embodiments may be a mammal, preferably a human.

In certain embodiments the disease to be treated is a proliferative disorder, particularly cancer. Non-limiting examples of cancers include bladder cancer, brain cancer, head and neck cancer, pancreatic cancer, lung cancer, breast cancer, ovarian cancer, uterine cancer, cervical cancer, endometrial cancer, esophageal cancer, colon cancer, colorectal cancer, rectal cancer, gastric cancer, prostate cancer, blood cancer, skin cancer, squamous cell carcinoma, bone cancer, and kidney cancer. Other cell proliferation disorders that can be treated using an immunoconjugate of the present invention include, but are not limited to neoplasms located in the: abdomen, bone, breast, digestive system, liver, pancreas, peritoneum, endocrine glands (adrenal, parathyroid, pituitary, testicles, ovary, thymus, thyroid), eye, head and neck, nervous system (central and peripheral), lymphatic system, pelvic, skin, soft tissue, spleen, thoracic region, and urogenital system. Also included are pre-cancerous conditions or lesions and cancer metastases. In certain embodiments the cancer is chosen from the group consisting of renal cell cancer, skin cancer, lung cancer, colorectal cancer, breast cancer, brain cancer, head and neck cancer. In some embodiments, particularly where the effector moiety of the immunoconjugate is IL-10, the disease to be treated is an inflammatory disorder. Non-limiting examples of inflammatory disorders include rheumatoid arthritis, psoriasis or Crohn's disease. A skilled artisan readily recognizes that in many cases the immunoconjugates may not provide a cure but may only provide partial benefit. In some embodiments, a physiological change having some benefit is also considered therapeutically beneficial. Thus, in some embodiments, an amount of immunoconjugate that provides a physiological change is considered an “effective amount” or a “therapeutically effective amount”. The subject, patient, or individual in need of treatment is typically a mammal, more specifically a human.

The immunoconjugates of the invention are also useful as diagnostic reagents. The binding of an immunoconjugate to an antigenic determinant can be readily detected by using a secondary antibody specific for the effector moiety. In one embodiment, the secondary antibody and the immunoconjugate facilitate the detection of binding of the immunoconjugate to an antigenic determinant located on a cell or tissue surface.

In some embodiments, an effective amount of an immunoconjugate of the invention is administered to a cell. In other embodiments, a therapeutically effective amount of an immunoconjugates of the invention is administered to an individual for the treatment of disease. For the prevention or treatment of disease, the appropriate dosage of an immunoconjugate of the invention (when used alone or in combination with one or more other additional therapeutic agents) will depend on the type of disease to be treated, the route of administration, the body weight of the patient, the type of immunoconjugate, the severity and course of the disease, whether the immunoconjugate is administered for preventive or therapeutic purposes, previous or concurrent therapeutic interventions, the patient's clinical history and response to the immunoconjugate, and the discretion of the attending physician. The practitioner responsible for administration will, in any event, determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual subject. Various dosing schedules including but not limited to single or multiple administrations over various time-points, bolus administration, and pulse infusion are contemplated herein.

The immunoconjugate is suitably administered to the patient at one time or over a series of treatments. Depending on the type and severity of the disease, about 1 μg/kg to 15 mg/kg (e.g. 0.1 mg/kg-10 mg/kg) of immunoconjugate can be an initial candidate dosage for administration to the patient, whether, for example, by one or more separate administrations, or by continuous infusion. One typical daily dosage might range from about 1 μg/kg to 100 mg/kg or more, depending on the factors mentioned above. For repeated administrations over several days or longer, depending on the condition, the treatment would generally be sustained until a desired suppression of disease symptoms occurs. One exemplary dosage of the immunoconjugate would be in the range from about 0.005 mg/kg to about 10 mg/kg. In other non-limiting examples, a dose may also comprise from about 1 microgram/kg body weight, about 5 microgram/kg body weight, about 10 microgram/kg body weight, about 50 microgram/kg body weight, about 100 microgram/kg body weight, about 200 microgram/kg body weight, about 350 microgram/kg body weight, about 500 microgram/kg body weight, about 1 milligram/kg body weight, about 5 milligram/kg body weight, about 10 milligram/kg body weight, about 50 milligram/kg body weight, about 100 milligram/kg body weight, about 200 milligram/kg body weight, about 350 milligram/kg body weight, about 500 milligram/kg body weight, to about 1000 mg/kg body weight or more per administration, and any range derivable therein. In non-limiting examples of a derivable range from the numbers listed herein, a range of about 5 mg/kg body weight to about 100 mg/kg body weight, about 5 microgram/kg body weight to about 500 milligram/kg body weight, etc., can be administered, based on the numbers described above. Thus, one or more doses of about 0.5 mg/kg, 2.0 mg/kg, 5.0 mg/kg or 10 mg/kg (or any combination thereof) may be administered to the patient. Such doses may be administered intermittently, e.g. every week or every three weeks (e.g. such that the patient receives from about two to about twenty, or e.g. about six doses of the immunoconjugate). An initial higher loading dose, followed by one or more lower doses may be administered. However, other dosage regimens may be useful. The progress of this therapy is easily monitored by conventional techniques and assays.

The immunoconjugates of the invention will generally be used in an amount effective to achieve the intended purpose. For use to treat or prevent a disease condition, the immunoconjugates of the invention, or pharmaceutical compositions thereof, are administered or applied in a therapeutically effective amount. Determination of a therapeutically effective amount is well within the capabilities of those skilled in the art, especially in light of the detailed disclosure provided herein.

For systemic administration, a therapeutically effective dose can be estimated initially from in vitro assays, such as cell culture assays. A dose can then be formulated in animal models to achieve a circulating concentration range that includes the IC₅₀ as determined in cell culture. Such information can be used to more accurately determine useful doses in humans.

Initial dosages can also be estimated from in vivo data, e.g., animal models, using techniques that are well known in the art. One having ordinary skill in the art could readily optimize administration to humans based on animal data.

Dosage amount and interval may be adjusted individually to provide plasma levels of the immunoconjugates which are sufficient to maintain therapeutic effect. Usual patient dosages for administration by injection range from about 0.1 to 50 mg/kg/day, typically from about 0.5 to 1 mg/kg/day. Therapeutically effective plasma levels may be achieved by administering multiple doses each day. Levels in plasma may be measured, for example, by HPLC.

In cases of local administration or selective uptake, the effective local concentration of the immunoconjugates may not be related to plasma concentration. One having skill in the art will be able to optimize therapeutically effective local dosages without undue experimentation.

A therapeutically effective dose of the immunoconjugates described herein will generally provide therapeutic benefit without causing substantial toxicity. Toxicity and therapeutic efficacy of an immunoconjugate can be determined by standard pharmaceutical procedures in cell culture or experimental animals. Cell culture assays and animal studies can be used to determine the LD₅₀ (the dose lethal to 50% of a population) and the ED₅₀ (the dose therapeutically effective in 50% of a population). The dose ratio between toxic and therapeutic effects is the therapeutic index, which can be expressed as the ratio LD₅₀/ED₅₀. Immunoconjugates that exhibit large therapeutic indices are preferred. In one embodiment, the immunoconjugate according to the present invention exhibits a high therapeutic index. The data obtained from cell culture assays and animal studies can be used in formulating a range of dosages suitable for use in humans. The dosage lies preferably within a range of circulating concentrations that include the ED₅₀ with little or no toxicity. The dosage may vary within this range depending upon a variety of factors, e.g., the dosage form employed, the route of administration utilized, the condition of the subject, and the like. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition (see, e.g., Fingl et al., 1975, in: The Pharmacological Basis of Therapeutics, Ch. 1, p. 1, incorporated herein by reference in its entirety).

The attending physician for patients treated with immunoconjugates of the invention would know how and when to terminate, interrupt, or adjust administration due to toxicity, organ dysfunction, and the like. Conversely, the attending physician would also know to adjust treatment to higher levels if the clinical response were not adequate (precluding toxicity). The magnitude of an administered dose in the management of the disorder of interest will vary with the severity of the condition to be treated, with the route of administration, and the like. The severity of the condition may, for example, be evaluated, in part, by standard prognostic evaluation methods. Further, the dose and perhaps dose frequency will also vary according to the age, body weight, and response of the individual patient.

Other Agents and Treatments

The immunoconjugates of the invention may be administered in combination with one or more other agents in therapy. For instance, an immunoconjugate of the invention may be co-administered with at least one additional therapeutic agent. The term “therapeutic agent” encompasses any agent administered to treat a symptom or disease in an individual in need of such treatment. Such additional therapeutic agent may comprise any active ingredients suitable for the particular indication being treated, preferably those with complementary activities that do not adversely affect each other. In certain embodiments, an additional therapeutic agent is an immunomodulatory agent, a cytostatic agent, an inhibitor of cell adhesion, a cytotoxic agent, an activator of cell apoptosis, or an agent that increases the sensitivity of cells to apoptotic inducers. In a particular embodiment, the additional therapeutic agent is an anti-cancer agent, for example a microtubule disruptor, an antimetabolite, a topoisomerase inhibitor, a DNA intercalator, an alkylating agent, a hormonal therapy, a kinase inhibitor, a receptor antagonist, an activator of tumor cell apoptosis, or an antiangiogenic agent.

Such other agents are suitably present in combination in amounts that are effective for the purpose intended. The effective amount of such other agents depends on the amount of immunoconjugate used, the type of disorder or treatment, and other factors discussed above. The immunoconjugates are generally used in the same dosages and with administration routes as described herein, or about from 1 to 99% of the dosages described herein, or in any dosage and by any route that is empirically/clinically determined to be appropriate.

Such combination therapies noted above encompass combined administration (where two or more therapeutic agents are included in the same or separate compositions), and separate administration, in which case, administration of the immunoconjugate of the invention can occur prior to, simultaneously, and/or following, administration of the additional therapeutic agent and/or adjuvant. Immunoconjugates of the invention can also be used in combination with radiation therapy.

Articles of Manufacture

In another aspect of the invention, an article of manufacture containing materials useful for the treatment, prevention and/or diagnosis of the disorders described above is provided. The article of manufacture comprises a container and a label or package insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, IV solution bags, etc. The containers may be formed from a variety of materials such as glass or plastic. The container holds a composition which is by itself or combined with another composition effective for treating, preventing and/or diagnosing the condition and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). At least one active agent in the composition is an immunoconjugate of the invention. The label or package insert indicates that the composition is used for treating the condition of choice. Moreover, the article of manufacture may comprise (a) a first container with a composition contained therein, wherein the composition comprises an immunoconjugate of the invention; and (b) a second container with a composition contained therein, wherein the composition comprises a further cytotoxic or otherwise therapeutic agent. The article of manufacture in this embodiment of the invention may further comprise a package insert indicating that the compositions can be used to treat a particular condition. Alternatively, or additionally, the article of manufacture may further comprise a second (or third) container comprising a pharmaceutically-acceptable buffer, such as bacteriostatic water for injection (BWFI), phosphate-buffered saline, Ringer's solution and dextrose solution. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, and syringes.

EXAMPLES

The following are examples of methods and compositions of the invention. It is understood that various other embodiments may be practiced, given the general description provided above.

Example 1 General Methods

Recombinant DNA Techniques

Standard methods were used to manipulate DNA as described in Sambrook et al., Molecular cloning: A laboratory manual; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989. The molecular biological reagents were used according to the manufacturer's instructions. General information regarding the nucleotide sequences of human immunoglobulins light and heavy chains is given in: Kabat, E. A. et al., (1991) Sequences of Proteins of Immunological Interest, Fifth Ed., NIH Publication No 91-3242.

DNA Sequencing

DNA sequences were determined by double strand sequencing.

Gene Synthesis

Desired gene segments where required were either generated by PCR using appropriate templates or were synthesized by Geneart AG (Regensburg, Germany) from synthetic oligonucleotides and PCR products by automated gene synthesis. In cases where no exact gene sequence was available, oligonucleotide primers were designed based on sequences from closest homologues and the genes were isolated by RT-PCR from RNA originating from the appropriate tissue. The gene segments flanked by singular restriction endonuclease cleavage sites were cloned into standard cloning/sequencing vectors. The plasmid DNA was purified from transformed bacteria and concentration determined by UV spectroscopy. The DNA sequence of the subcloned gene fragments was confirmed by DNA sequencing. Gene segments were designed with suitable restriction sites to allow sub-cloning into the respective expression vectors. All constructs were designed with a 5′-end DNA sequence coding for a leader peptide which targets proteins for secretion in eukaryotic cells. SEQ ID NOs 8-16 give exemplary leader peptides and polynucleotide sequences encoding them.

Preparation of IL-2R βγ Subunit-Fc Fusions and IL-2R α Subunit Fc Fusion

To study IL-2 receptor binding affinity, a tool was generated that allowed for the expression of a heterodimeric IL-2 receptor; the β-subunit of the IL-2 receptor was fused to an Fc molecule that was engineered to heterodimerize (Fc(hole)) (see SEQ ID NOs 17 and 18) using the “knobs-into-holes” technology (Merchant et al., Nat Biotech. 16, 677-681 (1998)). The γ-subunit of the IL-2 receptor was then fused to the Fc(knob) variant (see SEQ ID NOs 19 and 20), which heterodimerized with Fc(hole). This heterodimeric Fc-fusion protein was then used as a substrate for analyzing the IL-2/IL-2 receptor interaction. The IL-2R α-subunit was expressed as monomeric chain with an AcTev cleavage site and an Avi His tag (SEQ ID NOs 21 and 22). The respective IL-2R subunits were transiently expressed in HEK EBNA 293 with serum for the IL-2R βγ subunit construct and without serum for the α-subunit construct. The IL-2R βγ subunit construct was purified on protein A (GE Healthcare), followed by size exclusion chromatography (GE Healthcare, Superdex 200). The IL-2R α-subunit was purified via His tag on a NiNTA column (Qiagen) followed by size exclusion chromatography (GE Healthcare, Superdex 75). Amino acid and corresponding nucleotide sequences of various receptor constructs are given in SEQ ID NOs 17-22 and 255-268.

Preparation of Immunconjugates

Details about the generation and affinity maturation of antigen binding moieties directed to FAP can be found in the Examples appended to PCT patent application publication no. WO 2012/020006, which is incorporated herein by reference in its entirety. As described therein, various antigen binding domains directed to FAP have been generated by phage display, including the ones designated 4G8, 28H1 and 4B9 used in the following examples. Clone 28H1 is an affinity matured antibody based on parental clone 4G8, while clone 4B9 is an affinity matured antibody based on parental clone 3F2. The antigen binding domain designated 2B10 used herein is directed to the A2 domain of Tenascin C (TNC A2). Details about this and other antigen binding moieties directed against TNC A2 can be found in PCT patent application publication no. WO 2012/020038, which is incorporated herein by reference in its entirety. The antigen binding domain designated L19, directed against the Extra Domain B (EDB) of fibronectin is derived from the L19 antibody described in PCT publication WO 2007/128563. The antigen binding domains designated CH1A1A and CH1A1A 98/99 2F1 used herein are directed to CEA, and are described in more detail in PCT patent application no. PCT/EP2012/053390, which is incorporated herein by reference in its entirety.

The IL-2 quadruple mutant (qm) used as effector moiety in some of the following examples is described in detail in PCT patent application no. PCT/EP2012/051991, which is incorporated herein by reference in its entirety. Briefly, IL-2 qm is characterized by the following mutations:

-   -   1. T3A—knockout of predicted O-glycosylation site     -   2. F42A—knockout of IL-2/IL-2R α interaction     -   3. Y45A—knockout of IL-2/IL-2R α interaction     -   4. L72G—knockout of IL-2/IL-2R α interaction     -   5. C125A—mutation to avoid disulfide-bridged IL-2 dimers

The T3A mutation was chosen to eliminate the O-glycosylation site and obtain a protein product with higher homogeneity and purity when the IL-2 qm polypeptide or an immunoconjugate comprising it is expressed in eukaryotic cells such as CHO or HEK293 cells. The three mutations F42A, Y45A and L72G were chosen to interfere with the binding to CD25, the α-subunit of the IL-2 receptor. Reduced or abolished CD25 binding results in reduced activation-induced cell death (AICD), lack of preferential activation of regulatory T cells, as well as reduced toxicity (as described in EP 11153964.9).

The DNA sequences were generated by gene synthesis and/or classical molecular biology techniques and subcloned into mammalian expression vectors under the control of an MPSV promoter and upstream of a synthetic polyA site, each vector carrying an EBV OriP sequence.

Immunoconjugates as applied in the examples below were produced by co-transfecting exponentially growing HEK293-EBNA cells with the mammalian expression vectors using calcium phosphate-transfection. Alternatively, HEK293 cells growing in suspension were transfected by polyethylenimine (PEI) with the respective expression vectors. Alternatively, stably transfected CHO cell pools or CHO cell clones were used for production in serum-free media. Subsequently, the IgG-cytokine fusion proteins were purified from the supernatant. Briefly, IgG-cytokine fusion proteins were purified by one affinity step with protein A (HiTrap ProtA, GE Healthcare) equilibrated in 20 mM sodium phosphate, 20 mM sodium citrate pH 7.5. After loading of the supernatant, the column was first washed with 20 mM sodium phosphate, 20 mM sodium citrate, pH 7.5 and subsequently washed with 13.3 mM sodium phosphate, 20 mM sodium citrate, 500 mM sodium chloride, pH 5.45. The IgG-cytokine fusion protein was eluted with 20 mM sodium citrate, 100 mM sodium chloride, 100 mM glycine, pH 3. Fractions were neutralized and pooled and purified by size exclusion chromatography (HiLoad 16/60 Superdex 200, GE Healthcare) in final formulation buffer: 25 mM potassium phosphate, 125 mM sodium chloride, 100 mM glycine pH 6.7. Exemplary detailed purification procedures and results are given for selected constructs below. The protein concentration of purified protein samples was determined by measuring the optical density (OD) at 280 nm, using the molar extinction coefficient calculated on the basis of the amino acid sequence. Purity and molecular weight of immunoconjugates were analyzed by SDS-PAGE in the presence and absence of a reducing agent (5 mM 1,4-dithiotreitol) and stained with Coomassie blue (SimpleBlue™ SafeStain, Invitrogen). The NuPAGE® Pre-Cast gel system (Invitrogen) was used according to the manufacturer's instructions (4-20% Tris-glycine gels or 3-12% Bis-Tris). The aggregate content of immunoconjugate samples was analyzed using a Superdex 200 10/300GL analytical size-exclusion column (GE Healthcare) in 2 mM MOPS, 150 mM NaCl, 0.02% NaN₃, pH 7.3 running buffer at 25° C. The integrity of the amino acid backbone of reduced antibody light and heavy chains can be verified by NanoElectrospray Q-TOF mass spectrometry after removal of N-glycans by enzymatic treatment with Peptide-N Glycosidase F (Roche Molecular Biochemicals). The oligosaccharides attached to the Fc domain of the immunoconjugates are analysed by MALDI TOF-MS as described below. Oligosaccharides are enzymatically released from the immunoconjugates by PNGaseF digestion. The resulting digest solution containing the released oligosaccharides is either prepared directly for MALDI TOF-MS analysis or is further digested with EndoH glycosidase prior to sample preparation for MALDI TOF-MS analysis.

Example 2

FAP-targeted IgG-IL-2 qm fusion proteins were generated based on the FAP-antibodies 4G8, 28H1 and 4B9, wherein one single IL-2 quadruple mutant (qm) was fused to the C-terminus of one heterodimeric heavy chain as shown in FIG. 2A. Targeting to the tumor stroma where FAP is selectively expressed is achieved via the bivalent antibody Fab region (avidity effect). Heterodimerization resulting in the presence of a single IL-2 quadruple mutant is achieved by application of the knob-into-hole technology. In order to minimize the generation of homodimeric IgG-cytokine fusions the cytokine was fused to the C-terminus (with deletion of the C-terminal Lys residue) of the knob-containing IgG heavy chain via a (G₄S)₃ or G₄-(SG₄)₂ linker. The antibody-cytokine fusion has IgG-like properties. To reduce FcγR binding/effector function and prevent FcR co-activation, P329G L234A L235A (LALA) mutations were introduced in the Fc domain. The sequences of these immunoconjugates are given SEQ ID NOs 193, 269 and 205 (28H1 with (G₄S)₃ linker), SEQ ID NOs 193, 195 and 205 (28H1 with G₄-(SG₄)₂ linker), SEQ ID NOs 201, 203 and 205 (4G8 with G₄-(SG₄)₂ linker), SEQ ID NOs 207, 209 and 211 (4B9 with G₄-(SG₄)₂ linker), SEQ ID NOs 207, 271 and 211 (4B9 with (G₄S)₃ linker).

In addition, a CEA-targeted IgG-IL-2 qm fusion protein based on the anti-CEA antibody CH1A1A 98/99 2F1, a control DP47GS non-targeted IgG-IL-2 qm fusion protein wherein the IgG does not bind to a specified target, as well as a tumor stroma specific 2B10-based IgG-IL-2 qm fusion protein targeted against the A2 domain of tenascin-C were generated. The sequences of these immunoconjugates are given in SEQ ID NOs 275, 281 and 283 (CH1A1A 98/99 2F1 with G₄-(SG₄)₂ linker), SEQ ID NOs 277, 281 and 283 (CH1A1A 98/99 2F1 with (G₄S)₃ linker), SEQ ID NOs 219, 221 and 225 (DP47GS with G₄-(SG₄)₂ linker), SEQ ID NOs 219, 289 and 225 (DP47GS with (G₄S)₃ linker), SEQ ID NOs 285, 287 and 239 (2B10 with (G₄S)₃ linker). The constructs were generated by transient expression in HEK293 EBNA cells and purified as described above. FIGS. 3A-D to FIGS. 9A-D show exemplary chromatograms and elution profiles of the purification (A, B) as well as the analytical SDS-PAGE and size exclusion chromatographies of the final purified constructs (C, D). Transient expression yields were 42 mg/L for the 4G8-based, 20 mg/L for the 28H1-based, 10 mg/L for the 4B9-based, 5.3 mg/L for the CH1A1A 98/99 2F1-based, 36.7 mg/L for the 2B10-based and 13.8 mg/L for the DP47GS-based IgG-IL-2 qm immunoconjugate.

In addition a 28H1-based FAP-targeted IgG-IL-15 immunoconjugate is being generated, the sequences of which are given in SEQ ID NOs 193, 199 and 205. In the IL-15 polypeptide sequence the glutamic acid residue at position 53 is replaced by alanine to reduce binding to the α-subunit of the IL-15 receptor, and the asparagine residue at position 79 is replaced by alanine to abolish glycosylation. The IgG-IL-15 fusion protein is generated by transient expression and purified as described above.

FAP Binding Affinity

The FAP binding activity of the IgG-IL-2 qm immunoconjugates based on 4G8 and 28H1 anti-FAP antibodies were determined by surface plasmon resonance (SPR) on a Biacore machine in comparison to the corresponding unmodified IgG antibodies. Briefly, an anti-His antibody (Penta-His, Qiagen 34660) was immobilized on CMS chips to capture 10 nM His-tagged human FAP (20 s). Temperature was 25° C. and HBS-EP was used as buffer. Analyte concentration was 50 nM down to 0.05 nM at a flow rate of 50 μl/min (association: 300 s, dissociation: 900 s, regeneration: 60 s with 10 mM glycine pH 2). Fitting was performed based on a 1:1 binding model, RI=0, Rmax=local (because of capture format). The following table gives the estimated apperent bivalent affinities (pM avidity) as determined by SPR fitted with 1:1 binding RI=0, Rmax=local.

Hu FAP 4G8 IgG-IL-2 qm 100 pM 4G8 IgG  50 pM 28H1 IgG-IL-2 qm 175 pM 28H1 IgG 200 pM

The data show that within the error of the method affinity for human FAP is retained for the 28H1-based immunoconjugate or only slightly decreased for the 4G8-based immunoconjugate as compared to the corresponding unmodified antibodies.

Similarly, the affinity (K_(D)) of 4B9 IgG-IL-2 qm (16 pM), CH1A1A 98/99 2F1 IgG-IL-2 qm (400 pM), CH1A1A 98/99 2F1 IgG-IL-2 wt (see Example 4; 470 pM) and 2B10 IgG-IL-2 qm (150 pM, vs. 300 pM for unconjugated 2B10 IgG) to human FAP, CEA and TNC A2, respectively, were determined by SPR at 25° C. Cross-reactivity of the 4B9 and 2B10 antibodies to human, murine and cynomolgus FAP or TNC A2, respectively, was also confirmed.

Subsequently, the affinity of the 4G8- and 28H1-based IgG-IL-2 qm immunoconjugates to the IL-2R βγ heterodimer and the IL-2R α-subunit were determined by surface plasmon resonance (SPR) in direct comparison to the Fab-IL-2 qm-Fab immunoconjugate format described in PCT patent application no. PCT/EP2012/051991. Briefly, the ligands—either the human IL-2R α-subunit or the human IL-2R βγ heterodimer—were immobilized on a CMS chip. Subsequently, the 4G8- and 28H1-based IgG-IL-2 qm immunoconjugates or the 4G8- and 28H1-based Fab-IL-2 qm-Fab immunoconjugates for comparison were applied to the chip as analytes at 25° C. in HBS-EP buffer in concentrations ranging from 300 nM down to 1.2 nM (1:3 dil.). Flow rate was 30 μl/min and the following conditions were applied for association: 180 s, dissociation: 300 s, and regeneration: 2×30 s with 3 M MgCl₂ for IL-2R βγ heterodimer, 10 s with 50 mM NaOH for IL-2R α-subunit. 1:1 binding was applied for fitting (1:1 binding RI≠0, Rmax=local for IL-2R βγ, apparent K_(D), 1:1 binding RI=0, Rmax=local for IL-2R α). The respective K_(D) values are given in the table below.

Apparent K_(D) [nM] Hu IL-2R βγ Hu IL-2R α 4G8 IgG-IL-2 qm 5.9 No binding 4G8 Fab-IL-2 qm-Fab 10.4 No binding 28H1 IgG-IL-2 qm 6.2 No binding 28H1 Fab-IL-2 qm-Fab 11.4 No binding

The data show that the 4G8- and 28H1-based IgG-IL-2 qm immunoconjugates bind with at least as good affinity as the Fab-IL-2 qm-Fab immunoconjugates to the IL-2R βγ heterodimer, whereas they do not bind to the IL-2R α-subunit due to the introduction of the mutations interfering with CD25 binding. Compared to the respective Fab-IL-2 qm-Fab immunoconjugates the affinity of the IgG-IL-2 qm fusion proteins appears to be slightly enhanced within the error of the method.

Similarly, the affinity of further constructs (4B9, DP47GS, 2B10, CH1A1A 98/99 2F1) comprising either IL-2 wt (see Example 4) or IL-2 qm to the IL-2R βγ heterodimer and the IL-2R α-subunit was determined by SPR at 25° C. For all constructs the apparent K_(D) for the human IL-2R βγ heterodimer was between 6 and 12 nM (irrespective of whether the construct comprises IL-2 wt or IL-2 qm), whereas only the constructs comprising IL-2 wt bind to the IL-2R α-subunit at all (K_(D) for human IL-2R α around 20 nM).

Biological Activity Assays with IgG-Cytokine Immunoconjugates

The biological activity of FAP-targeted 4G8-based IgG-IL-2 qm fusions was investigated in several cellular assays in comparison to commercially available IL-2 (Proleukin, Novartis/Chiron) and/or the Fab-IL-2-Fab immunoconjugates described in EP 11153964.9.

Binding to FAP Expressing Cells

Binding of FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate to human FAP expressed on stably transfected HEK293 cells was measured by FACS. Briefly, 250 000 cells per well were incubated with the indicated concentration of the immunoconjugate in a round-bottom 96-well plate, incubated for 30 min at 4° C., and washed once with PBS/0.1% BSA. Bound immunoconjugate was detected after incubation for 30 min at 4° C. with FITC-conjugated AffiniPure F(ab′)2 Fragment goat anti-human F(ab′)2 Specific (Jackson Immuno Research Lab #109-096-097, working solution: 1:20 diluted in PBS/0.1% BSA, freshly prepared) using a FACS CantoII (Software FACS Diva). The results are shown in FIG. 10. The data show that the IgG-IL-2 qm immunoconjugate binds to FAP-expressing cells with an EC50 value of 0.9 nM, comparable to that of the corresponding 4G8-based Fab-IL-2 qm-Fab construct (0.7 nM).

IFN-γ Release by NK Cells (in Solution)

Subsequently, FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate was studied for the induction of IFN-γ release by NK92 cells as induced by activation of IL-2R βγ signaling. Briefly, IL-2 starved NK92 cells (100 000 cells/well in 96-U-well plate) were incubated with different concentrations of IL-2 immunoconjugate, comprising quadruple mutant IL-2, for 24 h in NK medium (MEM alpha from Invitrogen (#22561-021) supplemented with 10% FCS, 10% horse serum, 0.1 mM 2-mercaptoethanol, 0.2 mM inositol and 0.02 mM folic acid). Supernatants were harvested and the IFN-γ release was analysed using the anti-human IFN-γ ELISA Kit II from Becton Dickinson (#550612). Proleukin (Novartis) and 28H1-based Fab-IL-2 qm-Fab served as positive control for IL-2-mediated activation of the cells. FIG. 11 shows that the FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate is equally efficacious in inducing IFN-γ release as the affinity matured 28H1-based Fab-IL-2 qm-Fab immunoconjugate.

STAT5 Phosphorylation Assay

In a last set of experiments we studied the effects of the FAP-targeted 4G8-based IgG-IL-2 qm immunoconjugate on the induction of STAT5 phosphorylation compared to the 28H1 based Fab-IL-2-Fab and Fab-IL-2 qm-Fab immunoconjugates as well as Proleukin on human NK cells, CD4⁺ T cells, CD8⁺ T cells and T_(reg) cells from human PBMCs. Briefly, blood from healthy volunteers was taken in heparin-containing syringes and PBMCs were isolated. PBMCs were treated with the indicated immunoconjuagtes at the indicated concentrations or with Proleukin (Novartis) as control. After 20 min incubation at 37° C., PBMCs were fixed with pre-warmed Cytofix buffer (Becton Dickinson #554655) for 10 min at 37° C., followed by permeabilization with Phosflow Perm Buffer III (Becton Dickinson #558050) for 30 min at 4° C. Cells were washed twice with PBS containing 0.1% BSA before FACS staining was performed using mixtures of flow cytometry antibodies for detection of different cell populations and phosphorylation of STAT5. Samples were analysed using a FACSCantoII with HTS from Becton Dickinson. NK cells were defined as CD3⁻CD56⁺, CD8 positive T cells were defined as CD3⁺CD8⁺, CD4 positive T cells were defined as CD4⁺CD25⁻CD127⁺ and T_(reg) cells were defined as CD4⁺CD25⁺FoxP3⁺. For NK cells and CD8⁺ T cells that show no or very low CD25 expression (meaning that IL-2R signaling is mediated primarily via the IL-2R βγ heterodimer) the results show that the 4G8-based IgG-IL-2 qm immunoconjugate was <10-fold less potent in inducing STAT5 phosphorylation than Proleukin, but slightly more potent than 28H1-based Fab-IL-2-Fab and Fab-IL-2 qm-Fab immunoconjugates. On CD4⁺ T cells, that show a rapid up-regulation of CD25 upon stimulation, the 4G8-based IgG-IL-2 qm immunoconjugate was less potent than the 28H1 Fab-IL-2-Fab immunoconjugate, but slightly more potent than the 28H1 Fab-IL-2 qm-Fab immunoconjugate, and still showed induction of IL-2R signaling at saturating concentrations comparable to Proleukin and 28H1 Fab-IL-2-Fab. This is in contrast to T_(reg) cells where the potency of the 4G8-based IgG-IL-2 qm immunoconjugate was significantly reduced compared to the Fab-IL-2-Fab immunoconjugate due to the high CD25 expression on T_(reg) cells and the low binding affinity of the 4G8-based IgG-IL-2 qm immunoconjugate to CD25. As a consequence of the abolishment of CD25 binding in the 4G8-based IgG-IL-2 qm immunoconjugatee, IL-2 signaling in T_(reg) cells is only activated via the IL-2R heterodimer at concentrations where IL-2R signaling is activated on CD25-negative effector cells through the IL-2R βγ heterodimer. Taken together the 4G8-based IgG-IL-2 qm immunoconjugate described here is able to activate IL-2R signaling through the IL-2R βγ heterodimer, but does not result in a preferential stimulation of T_(reg) cells over other effector cells. The results of these experiments are shown in FIGS. 12A-D.

Binding of 2B10 IgG-IL-2 qm to TNC A2 Expressing Cells

Binding of TNC A2-targeted 2B10-based IgG-IL-2 qm immunoconjugate to human TNC A2 expressed on U87MG cells was measured by FACS. Briefly, 200 000 cells per well were incubated with the indicated concentration of the immunoconjugate in a round-bottom 96-well plate, incubated for 30 min at 4° C., and washed twice with PBS/0.1% BSA. Bound immunoconjugate was detected after incubation for 30 min at 4° C. with FITC-conjugated AffiniPure F(ab′)2 Fragment goat anti-human IgG Fcγ Specific (Jackson Immuno Research Lab #109-096-098, working solution: 1:20 diluted in PBS/0.1% BSA, freshly prepared) using a FACS CantoII (Software FACS Diva). The results are shown in FIG. 13. The data show that the 2B10 IgG-IL-2 qm immunoconjugate binds to TNC A2-expressing U87MG cells equally well as the corresponding unconjugated IgG.

Induction of NK92 Cell Proliferation by IgG-IL-2 Immunoconjugates

2B10 IgG-IL-2 qm, CH1A1A 98/99 2F1 IgG-IL-2 qm, CH1A1A 98/99 2F1 IgG-IL-2 wt, 4B9 IgG-IL-2 qm and 4B9 IgG-IL-2 wt immunoconjugates were tested for their ability to induce proliferation of NK92 cells. For proliferation assays, NK92 cells were starved in IL-2-free medium for 2 hours, 10000 cells/well seeded into a flat-bottom 96-well plate and then incubated for 3 days in a humidified incubator at 37° C., 5% CO₂ in the presence of the IL-2 immunoconjugates ( ). After 3 days, the ATP content of the cell lysates was measured using the CellTiter-Glo Luminescent Cell Viability Assay from Promega (#G7571/2/3). The percentage of growth was calculated setting a Proleukin (Novartis) concentration of 1.1 mg/ml to 100% proliferation and untreated cells without IL-2 stimulus to 0% proliferation. The results are shown in FIGS. 14 and 15. The data show that all constructs were able to induce NK92 cell proliferation, with the CH1A1A-based constructs being more active than the 2B10 IgG-IL-2 qm immunoconjugate, and the constructs comprising IL-2 wt being more active than the corresponding constructs with IL-2 qm.

Example 3

In general, the P329G LALA mutations that almost completely abolish FcγR interaction of human IgG₁ antibodies (see European patent application no. EP 11160251.2, incorporated herein by reference in its entirety) are introduced in order to reduce FcγR binding/effector function and thus prevent excessive cytokine release when the respective cytokine receptors are co-activated with FcγR signaling. In specific cases, for example when the antibody is targeting a highly tumor specific antigen, Fc effector functions may be retained by using an unmodified IgG Fc domain or may be even further enhanced via glycoengineering of the IgG Fc domain.

As an example thereof, we generated a CEA-targeted IgG-IL-2 qm immunoconjugate where one single IL-2 quadruple mutant was fused to the C-terminus of one heterodimeric heavy chain via a (SG₄)₃-linker based on the anti-CEA antibody clone CH1A1A. In this immunoconjugate the P329G LALA mutation was not included (see sequences of SEQ ID NOs 227, 229 and 231). The immunoconjugate was expressed and purified as human wildtype IgG- or glycoengineered IgG-IL-2 qm fusion protein as described below.

Preparation of (Glycoengineered) IgG-IL-2 qm Immunoconjugate

CEA-targeted CH1A1A-based IgG-IL-2 qm immunoconjugate was produced by co-transfecting HEK293-EBNA cells with the mammalian antibody expression vectors. Exponentially growing HEK293-EBNA cells were transfected by the calcium phosphate method. Alternatively, HEK293 cells growing in suspension are transfected by polyethylenimine. For the production of unmodified non-glycoengineered IgG-IL-2 qm immunoconjugate, the cells were transfected only with antibody heavy and light chain expression vectors in a 1:1 ratio (wherein the antibody heavy chain vector is a 1:1 mixture of two vectors: a vector for the heavy chain with the effector moiety, and a vector for the heavy chain without effector moiety).

For the production of the glycoengineered CEA-targeted IgG-IL-2 qm immunoconjugate, the cells were co-transfected with two additional plasmids, one for expression of a GnTIII fusion polypeptide (a GnT-III expression vector), and one for mannosidase II expression (a Golgi mannosidase II expression vector) at a ratio of 4:4:1:1, respectively. Cells were grown as adherent monolayer cultures in T flasks using DMEM culture medium supplemented with 10% FCS, and were transfected when they are between 50 and 80% confluent. For the transfection of a T150 flask, 15 million cells were seeded 24 hours before transfection in 25 ml DMEM culture medium supplemented with FCS (at 10% v/v final), and cells were placed at 37° C. in an incubator with a 5% CO₂ atmosphere overnight. For each T150 flask to be transfected, a solution of DNA, CaCl₂ and water was prepared by mixing 94 μg total plasmid vector DNA divided equally between the light and heavy chain expression vectors, water to a final volume of 469 μl, and 469 μl of a 1M CaCl₂ solution. To this solution, 938 μl of a 50 mM HEPES, 280 mM NaCl, 1.5 mM Na₂HPO₄ solution at pH 7.05 were added, mixed immediately for 10 sec and left to stand at room temperature for 20 sec. The suspension was diluted with 10 ml of DMEM supplemented with 2% FCS, and added to the T150 flask in place of the existing medium. Then additional 13 ml of transfection medium were added. The cells were incubated at 37° C., 5% CO₂ for about 17 to 20 hours, before the medium was replaced with 25 ml DMEM, 10% FCS. The conditioned culture medium was harvested approximately 7 days after the media exchange by centrifugation for 15 min at 210×g. The solution was sterile filtered (0.22 μm filter) and sodium azide in a final concentration of 0.01% w/v was added, and kept at 4° C.

The secreted wildtype or glycoengineered CEA IgG-IL-2 qm immunoconjugates were purified from cell culture supernatants by affinity chromatography using Protein A affinity chromatography, followed by a size exclusion chromatographic step on a HiLoad Superdex 200 column (GE Healthcare) as described above. Protein concentration, purity, molecular weight, aggregate content and integrity were analysed as described above.

Oligosaccharide Structure Analysis of (Glycoengineered) IgG-IL-2 qm Immunoconjugates

For determination of the relative ratios of fucose-containing and non-fucosylated oligosaccharide structures, released glycans of purified immunoconjugate material are analyzed by MALDI TOF mass spectrometry. The immunoconjugate sample (about 50 μg) is incubated overnight at 37° C. with 5 mU N-glycosidase F (QAbio; PNGaseF: E-PNG01) in 2 mM Tris, pH 7.0, in order to release the oligosaccharide from the protein backbone. For deamination of glycans acetic acid to a final concentration of 150 mM is added and incubated for 1 h at 37° C. For analysis by MALDI TOF mass spectrometry, 2 μL of the sample are mixed on the MALDI target with 2 μL DHB matrix solution (2, 5-dihydroxybenzoic acid [Bruker Daltonics #201346] dissolved in 50% ethanol/5 mM NaCl at 4 mg/ml) and analysed with MALDI TOF Mass Spectrometer Autoflex II instrument (Bruker Daltonics). Routinely, 50-300 shots are recorded and summed up to a single experiment. The spectra obtained are evaluated by the flex analysis software (Bruker Daltonics) and masses are determined for the each of the peaks detected. Subsequently, the peaks are assigned to fucose-containing or non-fucosylated carbohydrate structures by comparing the masses calculated and the masses theoretically expected for the respective structures (e.g. complex, hybrid and oligo- or high-mannose, respectively, with and without fucose).

For determination of the ratio of hybrid structures, the antibody samples are digested with N-glycosidase F and Endo-glycosidase H [QAbio; EndoH: E-EH02] concomitantly. N-glycosidase F releases all N-linked glycan structures (complex, hybrid and oligo- and high mannose structures) from the protein backbone and the Endo-glycosidase H cleaves all the hybrid type glycans additionally between the two N-acetylglucosamine (GlcNAc) residues at the reducing end of the glycan. This digest is subsequently treated and analysed by MALDI TOF mass spectrometry in the same way as described above for the N-glycosidase F digested sample. By comparing the pattern from the N-glycosidase F digest and the combined N-glycosidase F/Endo H digest, the degree of reduction of the signals of a specific carbohydrate structure is used to estimate the relative content of hybrid structures. The relative amount of each carbohydrate structure is calculated from the ratio of the peak height of an individual structure and the sum of the peak heights of all oligosaccharides detected. The amount of fucose is the percentage of fucose-containing structures related to all carbohydrate structures identified in the N-glycosidase F treated sample (e.g. complex, hybrid and oligo- and high-mannose structures). The degree of non-fucosylation is the percentage of structures lacking fucose relative to all carbohydrates identified in the N-glycosidase F treated sample (e.g. complex, hybrid and oligo- and high-mannose structures).

Antibody-Dependent Cell-Mediated Cytotoxicity Assay

The wildtype and glycoengineered CEA-targeted CH1A1A IgG-IL-2 qm immunoconjugates were compared in ADCC assays for their potential to mediate antibody mediated cellular cytotoxicity. Briefly, CEA-overexpressing A549 human tumor cells as target cells were collected, washed and resuspended in culture medium, stained with freshly prepared Calcein AM (Molecular Probes) at 37° C. for 30 min, washed three times, counted and diluted to 300 000 cells/ml. This suspension was transferred to a round-bottom 96-well plate (30000 cells/well), the respective immunoconjugate dilution was added and incubated for 10 min to allow the binding of the tested immunoconjugate to the cells prior to contact with effector cells. Effector to target ratio was 25 to 1 for freshly isolated PBMCs. Co-incubation was performed for 4 hours. Two different read-out systems were used: the release of lactate dehydrogenase (LDH) into supernatant after disintegration of the attacked cells, and the retention of Calcein in the remaining living cells. LDH from co-culture supernatant was collected and analyzed with a LDH detection Kit (Roche Applied Science). Substrate conversion by the LDH enzyme was measured with an ELISA absorbance reader (SoftMaxPro software, reference wavelengths: 490 nm versus 650 nm). Residual Calcein in living cells was analyzed in a fluorescence reader (Wallac VICTOR3 1420 Multilabel COUNTER (Perkin Elmer)) after removing the rest of supernatant from pelletized cells, one washing step in PBS prior to lysis, and fixation of the cells by borate buffer (50 mM borate, 0.1% Triton).

FIG. 16 shows the result based on LDH detection. A similar result was obtained based on the calcein retention (not shown). Both the constructs were able to mediate ADCC, the glycoengineered construct being similarly active as the corresponding glycoengineered unconjugated IgG. As expected, the non-glycoengineered construct showed reduced activity as compared to the glycoengineered construct.

Example 4

FAP-targeted 28H1- or 4B9-based, CEA-targeted CH1A1A 98/99 2F1-based and non-targeted DP47GS-based IgG-IL-2 immunoconjugates were generated wherein one single wildtype IL-2 polypeptide is fused to the C-terminus of one heterodimeric heavy chain. Heterodimerization resulting in an immunoconjugate with a single IL-2 moiety was achieved by application of the knob-into-hole technology. In order to minimize the generation of homodimeric IgG-IL-2 fusions proteins the cytokine was fused to the knob-containing heavy chain (with deletion of the C-terminal Lys residue) via a G₄-(SG₄)₂ or a (G₄S)₃ linker. The sequences of these immunoconjugates are given in SEQ ID NOs 193, 197 and 205 (28H1 with G₄-(SG₄)₂ linker) SEQ ID NOs 207, 273 and 211 (4B9 with (G₄S)₃ linker), SEQ ID NOs 277, 279 and 283 (CH1A1A 98/99 2F1 with (G₄S)₃ linker), SEQ ID NOs 219, 223 and 225 (DP47GS with G₄-(SG₄)₂ linker), SEQ ID NOs 219, 293 and 225 (DP47GS with (G₄S)₃ linker). The antibody-cytokine fusion has IgG-like properties. To reduce FcγR binding/effector function and prevent FcR co-activation, P329G LALA mutations were introduced in the Fc domain. Both constructs were purified according to the methods described above. Final purification was done by size exclusion chromatography (HiLoad 26/60 Superdex 200, GE Healthcare) in the final formulation buffer 20 mM histidine, 140 mM sodium chloride pH 6. FIGS. 17A-D to FIGS. 20A-D show the respective chromatograms and elution profiles of the purification (A, B) as well as the analytical SDS-PAGE and size exclusion chromatographies of the final purified constructs (C, D). Yield was 15.6 mg/L for the untargeted DP47GS IgG-IL-2 immunoconjugate, 26.7 mg/ml for the 28H1 IgG-IL-2 immunoconjugate, 4.6 mg/L for the CH1A1A 98/99 2F1 IgG-IL-2 immunoconjugate and 11 mg/L for the 4B9 IgG-IL-2 immunoconjugate.

Subsequently, their binding properties to FAP, respectively lack of binding, as well as binding to IL-2R βγ and IL-2R α chain were determined by SPR as described above (see Example 2). Cellular activity on immune effector cell populations and in vivo pharmacodynamic effects were also studied.

Example 5

FAP-targeted 4G8-based as well as TNC A2-targeted 2B10-based IgG-IL-10 immunoconjugates were constructed by fusing two different IL-10 cytokine formats to the C-terminus of the heavy chain of the heterodimeric IgG comprising a hole modification: either a single-chain IL-10 wherein a (G₄S)₄ 20-mer linker was inserted between two IL-10 molecules, or an engineered monomeric IL-10 (Josephson et al., J Biol Chem 275, 13552-7 (2000)). Both molecules were fused via a (G₄S)₃ 15-mer linker to the C-terminus of the heavy chain comprising a hole modification, with deletion of the C-terminal Lys residue. Heterodimerization resulting in only one heavy chain carrying an IL-10 moiety was achieved by application of the knob-into-hole technology. The IgG-cytokine fusion has IgG-like properties. To reduce FcγR binding/effector function and prevent FcR co-activation, P329G LALA mutations were introduced in the Fc domain of the immunoconjugate. The sequences of the respective constructs are given in SEQ ID NOs 233, 235 and 239 (2B10 with scIL-10), SEQ ID NOs 233, 237 and 239 (2B10 with monomeric IL-10 “IL-10M1”), SEQ ID NOs 241, 243 and 205 (4G8 with scIL-10), SEQ ID NOs 241, 245 and 205 (4G8 with IL-10M1). All these immunoconjugates were purified according to the methods described above. Subsequently, their binding properties to FAP or TNC A2, respectively, as well as their affinities to human IL-10R1 were determined by SPR using the ProteOn XPR36 biosensor. Briefly, the targets FAP or TNC A2 as well as human IL-10R1 were immobilized in vertical orientation on the sensorchip surface (FAP by standard amine coupling, TNC A2 and human IL-10R1 (both biotinylated via a C-terminal avi-tag) by neutravidin-capture). Subsequently, the IgG-IL-10 immunoconjugates were injected in six different concentrations, including a zero-concentration, as analytes in horizontal orientation.

After double-referencing, the sensorgrams were fit to a 1:1 interaction model to determine kinetic rate constants and affinities. The results from analytical SDS PAGE analysis and SPR-based affinity determinations to target antigens as well as IL-10 receptor are shown in FIGS. 21A-C and 22A-C. The data show that the immunoconjugates bind to TNC A2 or FAP with K_(D) values of 52 or 26 pM, respectively, while K_(D) values for IL-10 receptor are 520 and 815 pM.

Example 6

According to the methods described above, IgG-cytokine fusion proteins were generated and expressed consisting of one single 28H1-based or 4B9-based Fab region directed to FAP fused to the N-terminus of an Fc domain subunit comprising a hole modification, while the second Fab region of the IgG heavy chain with the knob modification was replaced by a cytokine moiety via a (G₄S)_(n) linker (n=1). See FIG. 2C for a schematic representation of this immunoconjugate format (also referred to as “1+1” format). Cytokine moieties used were the IL-2 quadruple mutant described above and in PCT patent application no. PCT/EP2012/051991 (see SEQ ID NO: 3), IL-7 and IFN-α. Corresponding sequences of the fusion polypeptides comprising the cytokine moiety, fused to the N-terminus of an Fc domain subunit comprising a knob modification via a linker peptide, are given in SEQ ID NOs 247 (comprising quadruple mutant IL-2), 249 (comprising IL-7), and 251 (comprising IFN-α). In these constructs, targeting of the immunoconjugate is achieved via the high affinity monovalent Fab region. This format may be recommended in cases where internalization of the antigen may be reduced using a monovalent binder. The immunoconjugates were produced, purified and analysed as described above. For constructs comprising IL-2 qm or IL-7, protein A affinity chromatography and size exclusion chromatography were combined in a single run. 20 mM histidine, 140 mM NaCl pH 6.0 was used as size exclusion chromatography and final formulation buffer. FIGS. 23A-C to 26A-D show the elution profiles and chromatograms of the purifications as well as the analytical SDS-PAGE and size exclusion chromatograms of the final purified constructs. The yields were 11 mg/L for the 4B9 “1+1” IgG-IL-2 qm, 43 mg/L for the 28H1 “1+1” IgG-IL-2 qm, 20.5 mg/L for the 4B9 “1+1” IgG-IL-7 and 10.5 mg/L for the 4B9 “1+1” IgG-IFN-α constructs.

The ability of “1+1” constructs comprising IL-2 qm to induce NK cell proliferation, compared to IgG-IL-2 qm immunoconjugates, was tested. NK-92 cells were starved for 2 h before seeding 10000 cells/well into 96-well-black-flat-clear bottom plates. The immunoconjugates were titrated onto the seeded NK-92 cells. After 72 h the ATP content was measured to determine the number of viable cells using the “CellTiter-Glo Luminescent Cell Viability Assay” Kit (Promega) according to the manufacturer's instructions. FIG. 27 shows that the “1+1” constructs are able to induce proliferation of NK-92 cells, being slightly less active than the corresponding IgG-IL-2 qm constructs.

The 4B9-based “1+1” constructs comprising IL-2 qm or IL-7 were tested for their ability to induce T cell proliferation, compared to IgG-IL-2 immunoconjugates. Peripheral blood mononuclear cells (PBMC) were prepared using Histopaque-1077 (Sigma Diagnostics Inc., St. Louis, Mo., USA). In brief, blood from buffy coats was diluted 5:1 with calcium- and magnesium-free PBS, and layered on Histopaque-1077. The gradient was centrifuged at 450×g for 30 min at room temperature (RT) without breaks. The interphase containing the PBMCs was collected and washed three times with PBS (350×g followed by 300×g for 10 min at RT). PBMCs were pre-stimulated with 1 μg/ml PHA-M (Sigma Aldrich #L8902) overnight, before they were labeled with 100 nM CFSE (carboxyfluorescein succinimidyl ester) for 15 min at 37° C. Cells were washed with 20 ml medium before recovering the labeled PBMCs for 30 min at 37° C. The cells were washed, counted, and 100000 cells were seeded into 96-well-U-bottom plates. The immunoconjugates were titrated onto the seeded cells for an incubation time of 6 days. Thereafter, cells were washed, stained for appropriate cell surface markers, and analyzed by FACS using a BD FACSCantoII. CD4 T cells were defined as CD3⁺/CD8⁻, and CD8 T cells as CD3⁺/CD8⁺.

FIGS. 28A-B show that the “1+1” constructs comprising either IL-2 qm or IL-7 are able to induce proliferation of PHA-activated CD4 (FIG. 28A) and CD8 T cells (FIG. 28B). As for NK cells, the “1+1” construct comprising IL-2 qm is slightly less active than an IgG-IL-2 qm construct.

The 4B9-based “1+1” construct comprising IFN-α was tested for its ability to inhibit Daudi cell proliferation, in comparison to Roferon A (Roche). Briefly, Daudi cells were labeled with 100 nM CFSE and seeded into a 96-well U-bottom plate (50′000 cells/well). The molecules were added at the indicated concentrations, followed by incubation for 3 days at 37° C. Proliferation was measured by analyzing the CFSE dilution, excluding dead cells from analysis by use of life/dead stain.

FIG. 29 shows that the construct was able to inhibit proliferation of Daudi cells, at least as potently as Roferon A.

Example 7

A single dose pharmacokinetics (PK) study was performed in tumor-free immunocompetent 129 mice for FAP-targeted IgG-IL2 immunoconjugates comprising either wild type or quadruple mutant IL-2, and untargeted IgG-IL-2 immunoconjugates comprising either wild type or quadruple mutant IL-2.

Female 129 mice (Harlan, United Kingdom), aged 8-9 weeks at the start of the experiment, were maintained under specific-pathogen-free conditions with daily cycles of 12 h light/12 h darkness according to committed guidelines (GV-Solas; Felasa; TierschG). The experimental study protocol was reviewed and approved by local government (P 2008016). After arrival, animals were maintained for one week to get accustomed to the new environment and for observation. Continuous health monitoring was carried out on a regular basis.

Mice were injected i.v. once with FAP-targeted 28H1 IgG-IL2 wt (2.5 mg/kg) or 28H1 IgG-IL2 qm (5 mg/kg), or untargeted DP47GS IgG-IL2 wt (5 mg/kg) or DP47GS IgG-IL2 qm (5 mg/kg). All mice were injected i.v. with 200 μl of the appropriate solution. To obtain the proper amount of immunoconjugate per 200 the stock solutions were diluted with PBS as necessary.

Mice were bled at 1, 8, 24, 48, 72, 96 h; and every 2 days thereafter for 3 weeks. Sera were extracted and stored at −20° C. until ELISA analysis. Immunoconjugate concentrations in serum were determined using an ELISA for quantification of the IL-2-immunoconjugate antibody (Roche-Penzberg). Absorption was measured using a measuring wavelength of 405 nm and a reference wavelength of 492 nm (VersaMax tunable microplate reader, Molecular Devices).

FIGS. 30A-B show the pharmacokinetics of these IL-2 immunoconjugates. Both the FAP-targeted (FIG. 30A) and untargeted (FIG. 30B) IgG-IL2 qm constructs have a longer serum half-life (approx. 30 h) than the corresponding IgG-IL-2 wt constructs (approx. 15 h). Of note, although the experimental conditions are not directly comparable, the serum half-life of the IL-2 immunoconjugates of the invention appears to be longer than the serum half-life of art-known “2+2” IgG-IL-2 immunoconjugates (see FIG. 1) as reported e.g. in Gillies et al., Clin Cancer Res 8, 210-216 (2002).

Concentration Compound Dose Formulation buffer (mg/mL) 28H1-IgG- 2.5 mg/kg 20 mM Histidine, 3.84 IL2 wt 140 mM NaCl, (= stock solution) pH 6.0 28H1-IgG-   5 mg/kg 20 mM Histidine, 2.42 IL2 qm    140 mM NaCl, (= stock solution)    pH 6.0 DP47GS-   5 mg/kg 20 mM Histidine, 3.74 IgG-IL2wt    140 mM NaCl, (= stock solution)    pH 6.0 DP47GS-   5 mg/kg 20 mM Histidine, 5.87 IgG- 140 mM NaCl, (= stock solution) IL2QM pH 6.0

Example 8

A biodistribution study was performed to assess tumor targeting of the immunoconjugates of the invention. FAP-targeted 28H1-based IgG-IL-2 qm was compared to FAP-targeted unconjugated 28H1 IgG and 4B9 IgG, and untargeted DP47GS IgG. Furthermore, a SPECT/CT imaging study was performed with 4B9 IgG-IL-2 qm, compared to DP47GS IgG-IL-2 qm, 4B9 IgG and DP47GS IgG.

DTPA Conjugation and ¹¹¹In Labeling

Solutions of 28H1 IgG-IL-2 qm, 28H1 IgG₁, 4B9 IgG-IL-2 qm, 4B9 IgG₁ and DP47 IgG₁ were dialysed against phosphate buffered saline (PBS, 15 mM). Two mg of the constructs (5 mg/ml) were conjugated with isothiocyanatobenzyl-diethylenetriaminepentaacetic acid (ITC-DTPA, Macrocyclis, Dallas, Tex.) in 0.1 M NaHCO₃, pH 8.2, under strict metal-free conditions, by incubation with a 5-fold molar excess of ITC-DTPA for one hour at room temperature (RT). Unconjugated ITC-DTPA was removed by dialysis against 0.1 M 2-(N-morpholino)ethanesulfonic acid (MES) buffer, pH 5.5.

The purified conjugates were radiolabeled by incubation with ¹¹¹In (Covidien BV, Petten, The Netherlands) in 0.1 M MES buffer, pH 5.5 containing 0.05% bovine serum albumin (BSA) and 0.05% Tween-80, at RT, under strict metal-free conditions for 30 min. After radiolabeling ethylenediaminetetraacetic acid (EDTA) was added to a final concentration of 5 mM to chelate the unbound ¹¹¹In. The ¹¹¹In labeled products were purified by gelfiltration on disposable G25M columns (PD10, Amersham Biosciences, Uppsala, Sweden). Radiochemical purity of purified ¹¹¹In labeled constructs were determined by instant thin-layer chromatography (ITLC) on TEC Control chromatography strips (Biodex, Shirley, N.Y.), using 0.1 M citrate buffer, pH 6.0, as the mobile phase. The specific activity of the ¹¹¹In-labeled preparations was 0.6-4.6 MBq/μg.

Lindmo Assay

The immunoreactive fraction of ¹¹¹In labeled antibody preparations was determined as described previously (Lindmo et al. (1984) J Immunol Methods 72, 77-89). Briefly, a serial dilution series of human embryonic kidney (HEK) cells transfected with fibroblast activation protein (FAP) cDNA (HEK-FAP cells) were incubated with 200 Bq of the ¹¹¹In-labeled construct at 37° C. for 1 hour. A duplicate of the lowest cell concentration was incubated in the presence of an excess of non-labeled construct to correct for non-specific binding. After incubation, the cells were washed, spun down and cell associated radioactivity was determined in the cell pellet in a gamma-counter (Wallac Wizzard 3″ 1480 automatic γ-counter, Pharmacia LKB). The immunoreactive fraction of the preparations ranged between 75-94%.

Animals

Female BALB/c nude mice (8-9 weeks, +/−20 g) were purchased from Janvier and housed in the Central Animal Facility of the Radboud University Nijmegen Medical Centre under standard conditions with 5 animals in individually ventilated cages with ad lib. access to food and water. After one week acclimatization the animals were inoculated s.c. with 10×10⁶ HEK-FAP cells in matrigel (1:3) in the left flank and optionally with 5×10⁶ HEK-293 cells in matrigel (1:3) in the right flank. Xenograft growth was monitored by caliper measurement (volume=(4/3·π)·(½·length)·(½·width)·(½·height). When xenografts reached a volume of 100 mm³, mice were injected i.v. with the ¹¹¹In-labeled constructs.

Biodistribution (28H1 IgG-IL-2 qm, 28H1 IgG₁, 4B9 IgG₁ and DP47GS IgG₁)

¹¹¹In-labeled constructs (5 MBq, 150 μg, 200 μl) were injected i.v. via the tail vein. Twenty-four hours after injection the animals were euthanized by suffocation in CO₂/O₂ atmosphere. Blood, muscle, xenograft, lung, spleen, pancreas, kidney, stomach (empty), duodenum (empty) and liver were collected, weighed and radioactivity was determined in a gamma-counter (Wallac Wizard). Standards of the injected dose (1%) were counted simultaneously and tissue uptake was calculated as % of the injected dose per gram tissue (% ID/g).

SPECT-CT Analysis (4B9 IgG-IL-2 qm, 4B9 IgG₁, DP47GS IgG-IL-2 qm and DP47GS IgG₁)

¹¹¹In-labeled 4B9-IgG-IL-2 qm, 4B9-IgG₁, DP47GS-IgG-IL-2 qm and DP47GS-IgG, were injected i.v. (20 MBq, 50, 150, 300 μg, 200 μl). At 4, 24, 72 and 144 hours after injection the animals were anesthetized with isoflurane/O₂ and scanned for 30 to 60 min in a U-SPECT II microSPECT/CT camera (MILabs, Utrecht, The Netherlands) equipped with a 1.0 mm mouse collimator. Computed tomography (CT) was performed directly after SPECT. Both SPECT (voxel size of 0.4 mm) and CT scans were reconstructed with MILabs software and SPECT and CT scans were co-registered to determine exact location of radio-signal. 3D images were created using Siemens Inveon Research Workplace software.

FIG. 31 shows that there is no significant difference between tissue distribution and tumor targeting of 28H1 and 4B9 IgG1 and 28H1 IgG-IL-2 qm at 24 hours (hence the cytokine does not significantly alter the tissue distribution and tumor targeting properties of the immunoconjugates), and that tumor-to-blood ratios for the FAP-targeted constructs are significantly greater than for the non-targeted DP47GS control IgG.

These results were confirmed in SPECT/CT imaging for the 4B9 IgG-IL-2 qm immunconjugate (data not shown). 4B9 IgG-IL-2 qm localized in the FAP-positive HEK-FAP but not in the FAP-negative HEK-293 control tumors, while the untargeted DP47GS immunoconjugate did not localize in either tumor. Unlike with the unconjugated IgGs, a weak uptake of 4B9 IgG-IL-2 qm was observed also in the spleen.

Example 9

Binding of 28H1-based IgG-IL-2 qm and a 28H1-based IgG-(IL-2 qm)₂ (i.e. a “2+2” format immunoconjugate as depicted in FIG. 1; sequences are shown in SEQ ID NOs 253 and 205) to NK 92 cells was compared. 200000 NK92 cells per well were seeded in a 96-well plate. The immunoconjugates were titrated onto the NK92 cells and incubated for 30 min at 4° C. to allow binding. The cells were washed twice with PBS containing 0.1% BSA to remove unbound constructs. For detection of the immunoconjugates a FITC-labeled anti-human Fc-specific antibody was added for 30 min at 4° C. The cells were again washed twice with PBS containing 0.1% BSA and analyzed by FACS using a BD FACSCantoII.

As illustrated in FIG. 32, the “2+2” immunoconjugate shows better binding to NK 92 cells than the corresponding “2+1” construct.

Example 10 Induction of Human PBMC Proliferation by IL-2 Immunoconjugates

Peripheral blood mononuclear cells (PBMC) were prepared using Histopaque-1077 (Sigma Diagnostics Inc., St. Louis, Mo., USA). In brief, venous blood from healthy volunteers was drawn into heparinized syringes. The blood was diluted 2:1 with calcium- and magnesium-free PBS, and layered on Histopaque-1077. The gradient was centrifuged at 450×g for 30 min at room temperature (RT) without breaks. The interphase containing the PBMCs was collected and washed three times with PBS (350×g followed by 300×g for 10 min at RT).

Subsequently, PBMCs were labeled with 40 nM CFSE (carboxyfluorescein succinimidyl ester) for 15 min at 37° C. Cells were washed with 20 ml medium before recovering the labeled PBMCs for 30 min at 37° C. The cells were washed, counted, and 100000 cells were seeded into 96-well-U-bottom plates. Pre-diluted Proleukin (commercially available wild-type IL-2) or IL2-immunoconjugates were titrated onto the seeded cells which were incubated for the indicated time points. After 4-6 days, cells were washed, stained for appropriate cell surface markers, and analyzed by FACS using a BD FACSCantoII. NK cells were defined as CD37CD56⁺, CD4 T cells as CD3⁺/CD8⁻, and CD8 T cells as CD3⁺/CD8⁺.

FIGS. 33A-C show proliferation of NK cells after incubation with different FAP-targeted 28H1 IL-2 immunoconjugates for 4 (FIG. 33A), 5 (FIG. 33B) or 6 (FIG. 33C) days. All tested constructs induced NK cell proliferation in a concentration-dependent manner. Proleukin was more efficacious than the immunoconjugates at lower concentrations, this difference no longer existed at higher concentrations, however. At earlier time points (day 4), the IgG-IL2 constructs appeared slightly more potent than the Fab-IL2-Fab constructs. At later time points (day 6), all constructs had comparable efficacy, with the Fab-IL2 qm-Fab construct being least potent at the low concentrations.

FIGS. 34A-C show proliferation of CD4 T-cells after incubation with different FAP-targeted 28H1 IL-2 immunoconjugates for 4 (FIG. 34A), 5 (FIG. 34B) or 6 (FIG. 34C) days. All tested constructs induced CD4 T cell proliferation in a concentration-dependent manner. Proleukin had a higher activity than the immunoconjugates, and the immunoconjugates comprising wild-type IL-2 were slightly more potent than the ones comprising quadruple mutant IL-2. As for the NK cells, the Fab-IL2 qm-Fab construct had the lowest activity. Most likely the proliferating CD4 T cells are partly regulatory T cells, at least for the wild-type IL-2 constructs.

FIGS. 35A-C show proliferation of CD8 T-cells after incubation with different FAP-targeted 28H1 IL-2 immunoconjugates for 4 (FIG. 35A), 5 (FIG. 35B) or 6 (FIG. 35C) days. All tested constructs induced CD8 T cell proliferation in a concentration-dependent manner. Proleukin had a higher activity than the immunoconjugates, and the immunoconjugates comprising wild-type IL-2 were slightly more potent than the ones comprising quadruple mutant IL-2. As for the NK and CD4 T cells, the Fab-IL2 qm-Fab construct had the lowest activity.

Example 11 Proliferation and Activation Induced Cell Death of IL-2 Activated PBMCs

Freshly isolated PBMCs from healthy donors were pre-activated overnight with PHA-M at 1 μg/ml in RPMI1640 with 10% FCS and 1% Glutamine. After pre-activation PBMCs were harvested, labeled with 40 nM CFSE in PBS, and seeded in 96-well plates at 100 000 cells/well. Pre-activated PBMCs were stimulated with different concentrations of IL-2 immunoconjugates (4B9 IgG-IL-2 wt, 4B9 IgG-IL-2 qm, 4B9 Fab-IL-2 wt-Fab, and 4B9 Fab-IL-2 qm-Fab). After six days of IL-2 treatment PBMCs were treated with 0.5 μg/ml activating anti-Fas antibody overnight. Proliferation of CD4 (CD3⁺CD8⁻) and CD8 (CD3⁺CD8⁺) T cells was analyzed after six days by CFSE dilution. The percentage of living T cells after anti-Fas treatment was determined by gating on CD3⁺ Annexin V negative living cells.

As shown in FIGS. 36A-B, all constructs induced proliferation of pre-activated T cells. At low concentrations the constructs comprising wild-type IL-2 wt were more active than the IL-2 qm-comprising constructs. IgG-IL-2 wt, Fab-IL-2 wt-Fab and Proleukin had similar activity. Fab-IL-2 qm-Fab was slightly less active than IgG-IL-2 qm. The constructs comprising wild-type IL-2 were more active on CD4 T cells than on CD8 T cells, most probably because of the activation of regulatory T cells. The constructs comprising quadruple mutant IL-2 were similarly active on CD8 and CD4 T cells.

As shown in FIG. 37, T cells stimulated with high concentrations of wild-type IL-2 are more sensitive to anti-Fas induced apoptosis than T cells treated with quadruple mutant IL-2.

Example 12

The untargeted DP47GS construct (see SEQ ID NO: 299 and 297 for VH and VL sequences, respectively) was further characterized. As described above, conjugates of DP47GS IgG with wild-type or quadruple mutant IL-2 were made. These constructs showed similar binding to IL-2R and induction of immune cell (e.g. NK cell, CD8⁺ cell and CD4⁺ cell) proliferation in vitro as corresponding targeted constructs (data not shown). In contrast to immunoconjugates targeting a tumor antigen, however, they did not accumulate in tumor tissue (see Example 8).

A further pharmacokinetic study (in addition to the one shown in Example 7) was performed with the untargeted DP47GS IgG-IL-2 constructs comprising either wild-type or quadruple mutant IL-2. Male C57BL/6J mice (n=6 per group) were injected i.v. with 0.3, 1, 3 or 10 mg/kg DP47GS IgG-IL-2 wt or DP47GS IgG-IL-2 qm construct. The injection volume was 1 ml for all mice. Blood samples were taken at 2, 4, 8, 24, 48, 72, 96 and 168 hours after injection (from 3 mice at each time point) and stored at −20° C. until analysis. The constructs were quantified in the serum samples by ELISA, using anti-Fab antibodies for capturing and detection of the constructs. All samples and calibration standards were diluted 1:25 in mouse serum (obtained from Bioreclamation) prior to the analysis. Briefly, streptavidin-coated 96 well plates (Roche) were washed three times for 10 sec with PBS/0.05% Tween 20, before incubation with 100 μl/well (0.5 μg/ml) biotinylated anti-human Fab antibody (M-1.7.10; Roche Diagnostics) for 1 hour at room temperature. After washing the plate again three times with PBS/0.05% Tween 20, 50 μl/well of the serum samples or calibration standards and 50 μl/well PBS/0.5% BSA were added to give a final sample dilution of 1:50. Samples were incubated for 1 hour at room temperature, followed by washing the plate again three times with PBS/0.05% Tween 20. Next, the plate was incubated with 100 μl/well (0.5 μg/ml) digoxigenin-labeled anti-human Fab antibody (M-1.19.31; Roche Diagnostics) for 1 hour at room temperature, washed, incubated with 100 μl/well anti-digoxigenin POD (Roche Diagnostics Cat#11633716001) for 1 hour at room temperature, and washed again. Finally, 100 μl/well TMB peroxidase substrate (Roche Diagnostics Cat#11484281001) was added for about 5 minutes, before the substrate reaction was stopped with 50 μl/well 2N HCl. The plate was read within 2 minutes after stopping the reaction at 450 nm with a reference wavelength of 650 nm.

The result of this study is shown in FIGS. 38A-B. Both constructs showed long serum half life, with the construct comprising quadruple mutant IL-2 (FIG. 38B) being even longer lived than the one comprising wild-type IL-2 (FIG. 38A).

In addition, the lack of binding of DP47GS IgG to various proteins as well as human cells (PBMCs) was confirmed.

The binding specificity (or lack of such) of the DP47GS antibody was assessed in an ELISA-based test system with a panel of different unrelated antigens. The test was performed on 384 well MaxiSorp™ microtiter plates (Thermo Scientific Nunc, Cat#460372). After each incubation step the plates were washed three times with PBS/0.05% Tween-20. First, the different antigens, diluted in PBS, were coated on plates overnight at 6° C. The test concentrations and detailed information for the used antigens are listed in the table below.

Test con- centration Antigen Source Supplier Cat# [μg/ml] Histons calf Roche 10223565601 2 thymus Diagnostics BSA bovine Roche 10735108001 2 Fraction V Diagnostics Insulin human Roche 11376497001 2 Diagnostics Cardiolipin bovine Sigma-Aldrich C1649 2 Heparin porcine Sigma-Aldrich H9902 2 CD40 (hFc) human Sino Biological 1077-H03H 1 Parathyroid human AnaSpec    20690 0.5 hormone aa 1-34 (PTH) (biotinylated) dsDNA calf thymus Sigma-Aldrich D4522 0.16 Hemocyanin keyhole Sigma-Aldrich H7017 0.22 limpet Actin beta 2 human Cytoskeleton APHL99 0.67 Streptavidin Streptomyces Roche 11721674001 1 avidinii Diagnostics Gelatin bovine Roche 11111965001 2% Diagnostics blocking buffer E. coli lysate E. coli inhouse — diluted 1:600

Thereafter, the wells were blocked with 2% gelatin in water for 1 hour at room temperature (RT). The DP47GS antibody (1 μg/ml in PBS) was incubated with the panel of captured antigens for 1.5 hours at RT. Bound antibody was detected using anti-human IgG antibody-HRP conjugate (GE Healthcare, Cat#9330V; diluted 1:1000 in PBS with 0.2% Tween-20 and 0.5% gelatin). After 1 hour incubation the plates were washed 6 times with PBS/0.05% Tween-20 and developed with freshly prepared BM blue POD substrate solution (BM blue: 3,3′-5,5′-tetramethylbenzidine, Roche Diagnostics, Cat#11484281001) for 30 minutes at RT. Absorbance was measured at 370 nm. The blank value was defined without addition of antibody. An inhouse human IgG₁ antibody which exhibits unspecific binding to almost all of the captured antigens served as positive control.

The result of this experiment is shown in FIG. 39. The DP47GS antibody showed no binding to any of the captured antigens. The detected signals were in the range of the control samples without antibody.

Finally, the binding of the DP47GS antibody to human PBMCs was assessed. Since in the course of a typical immune response the combination of cell surface-presented proteins changes dramatically, binding was tested on PBMCs directly after isolation from healthy adults as well as after in vitro activation with two different stimuli.

Human PBMCs were isolated by Ficoll density gradient centrifugation from buffy coats or from heparinized fresh blood from healthy volunteers using Histopaque 1077 (Sigma-Aldrich, Germany). PBMCs were either directly subjected to binding assays (fresh PBMCs) or cultured and stimulated further. PBMCs were cultured at a cell density of 2×10⁶ cells/ml in T cell medium consisting of RPMI 1640 (Gibco) supplemented with 10% (v/v) heat-inactivated FBS (PAA Laboratories), 1 mM sodium pyruvate (Sigma-Aldrich), 1% (v/v) L-alanyl-L-gluthamine (Biochrom) and 10 nM β-mercaptoethanol (Sigma-Aldrich) at 37° C. For in vitro stimulation, Proleukin (200 U/ml, Novartis) and phytohaemagglutinin (PHA-L; 2 μg/mL, Sigma-Aldrich) were added during six days of cultivation (PHA-L activated PBMC). For in vitro re-stimulation, 6-well cell culture plates were coated with mouse anti-human CD3 (clone KT3, 1 μg/ml) and mouse anti-human CD28 antibodies (clone 28.2, 2 μg/ml, both from eBioscience) and PHA-L activated PBMC were added for additional 24 hours (re-stimulated PBMC). Binding of DP47GS antibody (with or without the L234A L235A (LALA) P329G mutation in the Fc domain) to cell surface proteins was monitored for a five-fold serial dilution series (highest concentration 200 nM) using a goat anti-human IgG Fc-specific secondary antibody conjugated to fluorescein isothiocyanate (FITC) (Jackson Laboratories) and flow cytometric analysis. All assays were performed at 4° C. to prevent internalization of surface proteins. Incubation of primary and secondary antibody was for 2 hours and for 1 hour, respectively. To allow simultaneous typing of leukocytes, combinations of fluorochrome-labeled mouse anti-human CD14, CD15, CD4, CD19 (all Biolegend), NKp46, CD3, CD56, CD8 (all BD Pharmingen) were added to the secondary antibody. Propidium iodide (1 μg/ml) was added directly before measurement on a FACSCantoII device running FACS Diva software (both BD Bioscience) to exclude permeable dead cells. Propidium iodide negative living cells were gated for T cells (CD14⁻CD3⁺CD4⁺/CD8⁺), B cells (CD14⁻CD19⁺), NK Cells (CD14⁻NKp46⁺/CD56⁺) or monocytes/neutrophils (CD3⁻CD56⁻CD14⁺/CD15⁺). The median FITC fluorescence of the various leukocyte types was determined as indicator for bound primary antibody and blotted against the primary antibody concentration using Prism4 (GraphPad Software).

As shown in FIGS. 40A-L, the DP47GS IgG antibody without Fc mutation showed binding only to Fcγ receptor bearing cells, e.g. NK cells and monocytes/neutrophils. No binding of DP47GS (LALA P329G) was detected on human PBMCs, regardless of their activation status. The LALA P329G mutation in the Fc domain completely abolished binding also to Fcγ receptor bearing cells.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, the descriptions and examples should not be construed as limiting the scope of the invention. The disclosures of all patent and scientific literature cited herein are expressly incorporated in their entirety by reference. 

The invention claimed is:
 1. An immunoconjugate comprising a mutant interleukin-2 (IL-2) polypeptide and an antigen binding moiety, wherein said mutant IL-2 polypeptide is a mutant of a human IL-2 polypeptide comprising the amino acid sequence of SEQ ID NO: 2 and comprises three amino acid substitutions at positions corresponding to positions 42, 45, and 72 of SEQ ID NO: 2, wherein said three amino acid substitutions are F42A, Y45A and L72G; and wherein said antigen binding moiety is an IgG1 subclass immunoglobulin molecule specific for Carcinoembryonic Antigen (CEA), comprising a heavy chain variable region comprising, according to the Kabat numbering system, (i) the heavy chain CDR1, (ii) heavy chain CDR2 and (iii) heavy chain CDR3 of the heavy chain variable region sequence of SEQ ID NO: 191, and a light chain variable region comprising, according to the Kabat numbering system, (i) the light chain CDR1, (ii) light chain CDR2, and (iii) light chain CDR3 of the light chain variable region of SEQ ID NO:
 189. 2. A pharmaceutical composition comprising the immunoconjugate of claim 1 and a pharmaceutically acceptable carrier.
 3. The immunoconjugate of claim 1, wherein said mutant IL-2 polypeptide further comprises one or more of the amino acid substitutions at positions corresponding to positions 3 or 125 of SEQ ID NO: 2, wherein said one or more of the amino acid substitutions are T3A or C125A.
 4. The immunoconjugate of claim 1, wherein said mutant IL-2 polypeptide comprises the sequence of SEQ ID NO:
 3. 5. The immunoconjugate of claim 4, wherein said mutant IL-2 polypeptide is joined at its amino-terminal amino acid to the carboxy-terminal amino acid of one of the immunoglobulin heavy chains.
 6. The immunoconjugate of claim 5, wherein the immunoconjugate comprises not more than one mutant IL-2 polypeptide.
 7. The immunoconjugate of claim 6, wherein the IgG₁ subclass immunoglobulin molecule comprises in the Fc domain a modification promoting heterodimerization of two non-identical immunoglobulin heavy chains.
 8. The immunoconjugate of claim 7, wherein the modification is a knob-into-hole modification, comprising a knob modification in one of the immunoglobulin heavy chains and a hole modification in the other one of the immunoglobulin heavy chains.
 9. The immunoconjugate of claim 8, wherein the knob modification comprises the amino acid substitution T366W in one of the two immunoglobulin heavy chains, and the hole modification comprises the amino acid substitutions T366S, L368A and Y407V in the other one of the two immunoglobulin heavy chains, according to the EU numbering of Kabat.
 10. The immunoconjugate of claim 9, wherein the immunoglobulin heavy chain comprising the knob modification further comprises the amino acid substitution S354C, and the immunoglobulin heavy chain comprising the hole modification further comprises the amino acid substitution Y349C, according to the EU numbering of Kabat.
 11. The immunoconjugate of claim 4, wherein the IgG₁ molecule comprises in its Fc domain one or more amino acid mutations that reduce the binding affinity of the immunoconjugate to an FcγRIIIa, FcγRI or FcγRIIa receptor.
 12. The immunoconjugate of claim 11, wherein the IgG₁ molecule comprises the amino acid mutations L234A, L235A and P329G, according to the EU numbering of Kabat.
 13. The immunoconjugate of claim 4, wherein the heavy chain variable region comprises a sequence that is at least about 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 191, and the light chain variable region comprises a sequence that is at least about 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO:
 189. 14. The immunoconjugate of claim 1, wherein said mutant IL-2 polypeptide is joined at its amino-terminal amino acid to the carboxy-terminal amino acid of one of the heavy chains of said immunoglobulin molecule.
 15. The immunoconjugate of claim 14, wherein the immunoconjugate comprises not more than one mutant IL-2 polypeptide.
 16. The immunoconjugate of claim 1, wherein the IgG₁ subclass immunoglobulin molecule comprises in the Fc domain a modification promoting heterodimerization of two non-identical immunoglobulin heavy chains.
 17. The immunoconjugate of claim 16, wherein the modification is a knob-into-hole modification, comprising a knob modification in one of the immunoglobulin heavy chains and a hole modification in the other one of the immunoglobulin heavy chains.
 18. The immunoconjugate of claim 17, wherein the knob modification comprises the amino acid substitution T366W in one of the two immunoglobulin heavy chains, and the hole modification comprises the amino acid substitutions T366S, L368A and Y407V in the other one of the two immunoglobulin heavy chains, according to the EU numbering of Kabat.
 19. The immunoconjugate of claim 18, wherein the immunoglobulin heavy chain comprising the knob modification further comprises the amino acid substitution S354C, and the immunoglobulin heavy chain comprising the hole modification further comprises the amino acid substitution Y349C, according to the EU numbering of Kabat.
 20. The immunoconjugate of claim 1, wherein the IgG₁ molecule comprises in its Fc domain one or more amino acid mutations that reduce the binding affinity of the immunoconjugate to an FcγRIIIa, FcγRI or FcγRIIa receptor.
 21. The immunoconjugate of claim 20, wherein the IgG₁ molecule comprises the amino acid mutations L234A, L235A and P329G, according to the EU numbering of Kabat.
 22. The immunoconjugate of claim 1, wherein the heavy chain variable region comprises a sequence that is at least about 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 191, and the light chain variable region comprises a sequence that is at least about 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO:
 189. 23. The immunoconjugate of claim 1, comprising a polypeptide sequence that is at least about 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 277, a polypeptide sequence that is at least about 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO: 281, and a polypeptide sequence that is at least about 90%, 95%, 96%, 97%, 98% or 99% identical to SEQ ID NO:
 283. 